(1) “Acceptable” means any device, equipment, or appliance that
is either approved by MSHA and maintained in permissible condition, or
is listed or labeled for the class and location under Part I of this chapter.
(2) “Bulkhead” means an airtight structure separating the working
chamber from free air or from another chamber under a lesser pressure
than the working pressure.
(3) “Caisson” means a wood, steel, concrete or reinforced concrete,
air- and water-tight chamber in which it is possible for persons to work
under air pressure greater than atmospheric pressure to excavate material
below water level.
(4) “Cofferdam” means a watertight barricade or enclosure erected,
sunk, driven or otherwise fabricated to permit the performance of work
where hydrostatic pressure exists.
(5) “Decanting” means a method used for decompressing under
emergency circumstances. In this procedure, the employees are brought
to atmospheric pressure with a very high gas tension in the tissues and
then immediately recompressed in a second and separate chamber or lock.
(6) “Emergency locks” means a lock designed to hold and permit
the quick passage of an entire shift of employees.
(7) “High air” means air pressure used to supply power to pneumatic
tools and devices.
(8) “Low air” means air supplied to pressurize working chambers
and locks.
(9) “Man lock” means a chamber through which persons pass from
one air pressure environment into another.
(10) “Materials lock” means a chamber through which materials
and equipment pass from one air pressure environment into another.
(11) “Medical lock” means a special chamber in which employees
are treated for decompression illness. It may also be used in pre-employment
physical examinations to determine the adaptability of the prospective
employee to changes in pressure.
(12) “Rapid excavation machine” means tunnel boring machines,
shields, roadheaders, or any other similar excavation machine.
(13) “Normal condition” means one during which exposure to compressed
air is limited to a single continuous working period followed by a single
decompression in any given 24-hour period; the total time of exposure
to compressed air during the single continuous working period is not interrupted
by exposure to normal atmospheric pressure, and a second exposure to compressed
air does not occur until at least 12 consecutive hours of exposure to
normal atmospheric pressure has elapsed since the employee has been under
pressure.
(14) “Pressure” means a force acting on a unit area. Usually shown
as pounds per square inch. (p.s.i.)
(15) “Absolute pressure” (p.s.i.a.) means the sum of the atmospheric
pressure and gauge pressure (p.s.i.g.)
(16) “Atmospheric pressure” means the pressure of air at sea level,
usually 14.7 p.s.i.a. (1 atmosphere), or 0 p.s.i.g.
(17) “Gauge pressure” (p.s.i.g.) means pressure measured by a
gauge and indicating the pressure exceeding atmospheric.
(18) “Safety screen” means an air- and water-tight diaphragm
placed across the upper part of a compressed air tunnel between the face
and bulkhead, in order to prevent flooding the crown of the tunnel between
the safety screen and the bulkhead, thus providing a safe means of refuge
and exit from a flooding or flooded tunnel.
(19) “Special decompression chamber” means a chamber to provide
greater comfort for employees when the total decompression time exceeds
75 minutes.
(20) “Working chamber” means the space or compartment under air
pressure in which the work is being done.
(21) “C.F.R.” means Code of Federal Regulations.
(22) “MSHA” means Mine Safety and Health Administration.
(23) “NIOSH” means National Institute for Occupational Safety
and Health.
(a) This section applies to the construction of underground tunnels,
shafts, chambers, and passageways. This section also applies to cut-and-cover
excavations which are both physically connected to ongoing underground
construction operations within the scope of this section, and covered
in such a manner as to create conditions characteristic of underground
construction.
(b) This section does not apply to excavation and trenching operations
covered by Part N of this chapter, such as foundation operations for
above-ground structures that are not physically connected to underground
construction operations, and surface excavation.
(c) The employer shall comply with the requirements of this part and
chapter in addition to applicable requirements of chapter
296-36 WAC, Safety standards-Compressed air work.
(2) Access and egress.
(a) Each operation shall have a check-in/check-out system that will
provide positive identification of every employee underground. An accurate
record of identification and location of the employees shall be kept
on the surface. This procedure is not required when the construction
of underground facilities designed for human occupancy has been sufficiently
completed so that the permanent environmental controls are effective,
and when the remaining construction activity will not cause any environmental
hazard, or structural failure within the facilities.
(b) The employer shall provide and maintain safe means of access and
egress to all work stations.
(c) The employer shall provide access and egress in such a manner that
employees are protected from being struck by excavators, haulage machines,
trains, and other mobile equipment.
(d) The employer shall control access to all openings to prevent unauthorized
entry underground. Unused chutes, manways, or other openings shall be
tightly covered, bulkheaded, or fenced off, and shall be posted with
warning signs indicating “keep out” or similar language. Completed or
unused sections of the underground facility shall be barricaded.
(3) Safety instruction. All employees shall be instructed in the recognition
and avoidance of hazards associated with underground construction activities
including, where appropriate, the following subjects:
(a) Air monitoring;
(b) Ventilation;
(c) Confined space entry procedures;
(d) Permit-required confined space entry procedures;
(e) Illumination;
(f) Communications;
(g) Flood control;
(h) Mechanical equipment;
(i) Personal protective equipment;
(j) Explosives;
(k) Fire prevention and protection; and
(l) Emergency procedures, including evacuation plans and check-in/check-out
systems.
(4) Notification.
(a) Oncoming shifts shall be informed of any hazardous occurrences
or conditions that have affected, or might affect employee safety, including
liberation of gas, equipment failures, earth or rock slides, cave-ins,
floodings, fire(s), or explosions.
(b) Information specified in (a) of this subsection shall be recorded
in a shift journal which shall be current prior to the end of each shift,
and shall be located aboveground.
(c) Oncoming supervisory personnel shall read the notification prior
to going underground, and shall signify their understanding of the contents
by affixing their respective initials to the log.
(d) The hazard notification log shall be retained on the site until
the completion of the project.
(e) The employer shall establish and maintain direct communications
for coordination of activities with other employers whose operations
at the jobsite affect or may affect the safety of employees underground.
(5) Communications.
(a) When natural unassisted voice communication is ineffective, a power-assisted
means of voice communication shall be used to provide communication
between the work face, the bottom of the shaft, and the surface.
(b) Two effective means of communication, at least one of which shall
be voice communication, shall be provided in all shafts which are being
developed or used either for personnel access or for hoisting. Additional
requirements for hoist operator communication are contained in subsection
(22)(c)(xv) of this section.
(c) Powered communication systems shall operate on an independent power
supply, and shall be installed so that the use of or disruption of any
one phone or signal location will not disrupt the operation of the system
from any other location.
(d) Communication systems shall be tested upon initial entry of each
shift to the underground, and as often as necessary at later times,
to ensure that they are in working order.
(e) Any employee working alone underground in a hazardous location,
who is both out of the range of natural unassisted voice communication
and not under observation by other persons, shall be provided with an
effective means of obtaining assistance in an emergency.
(6) Emergency provisions. Hoisting capability. When a shaft is used as
a means of egress, the employer shall make advance arrangements for power-assisted
hoisting capability to be readily available in an emergency, unless the
regular hoisting means can continue to function in the event of an electrical
power failure at the jobsite. Such hoisting means shall be designed so
that the load hoist drum is powered in both directions of rotation and
so that the brake is automatically applied upon power release or failure.
(7) Self-rescuers. The employer must provide self-rescuers certified
by the National Institute for Occupational Safety and Health under
42 CFR part 84. The respirators must be immediately available
to all employees at work stations in underground areas where employees
might be trapped by smoke or gas. The selection, issuance, use,
and care of respirators must be in accordance with the requirements
of chapter 296-842
WAC.
(8) Designated person. At least one designated person shall be on duty
aboveground whenever any employee is working underground. This designated
person shall be responsible for securing immediate aid and keeping an
accurate record of the number, identification, and location of employees
who are underground in case of emergency. The designated person must not
be so busy with other responsibilities that the personnel counting and
identification function is encumbered.
(9) Emergency lighting. Each employee underground shall have an acceptable
portable hand lamp or cap lamp in his or her work area for emergency use,
unless natural light or an emergency lighting system provides adequate
illumination for escape.
(10) Rescue teams.
(a) On jobsites where 25 or more employees work underground at one
time, the employer shall provide (or make arrangements in advance with
locally available rescue services to provide) at least two 5-person
rescue teams, one on the jobsite or within one-half hour travel time
from the entry point, and the other within 2 hours travel time.
(b) On jobsites where less than 25 employees work underground at one
time, the employer shall provide (or make arrangements in advance with
locally available rescue services to provide) at least one 5-person
rescue team to be either on the jobsite or within one-half hour travel
time from the entry point.
(c) Rescue team members shall be qualified in rescue procedures, the
use and limitations of breathing apparatus, and the use of fire fighting
equipment. Qualifications shall be reviewed not less than annually.
(d) On jobsites where flammable or noxious gases are encountered or
anticipated in hazardous quantities, rescue team members shall practice
donning and using pressure demand mode, self-contained breathing apparatuses
monthly.
(e) The employer shall ensure that rescue teams are familiar with conditions
at the jobsite.
(11) Hazardous classifications.
(a) Potentially gassy operations. Underground construction operations
shall be classified as potentially gassy if either:
(i) Air monitoring discloses 10 percent or more of the lower explosive
limit for methane or other flammable gases measured at 12 inches (304.8
mm) +/-0.25 inch (6.35 mm) from the roof, face, floor, or walls in
any underground work area for more than a 24-hour period; or
(ii) The history of the geographical area or geological formation
indicates that 10 percent or more of the lower explosive limit for
methane or other flammable gases is likely to be encountered in such
underground operations.
(b) Gassy operations. Underground construction operations shall be
classified as gassy if:
(i) Air monitoring discloses 10 percent or more of the lower explosive
limit for methane or other flammable gases measured at 12 inches (304.8
mm) +/-0.25 inch (6.35 mm) from the roof, face, floor, or walls in
any underground work area for three consecutive days; or
(ii) There has been an ignition of methane or of other flammable
gases emanating from the strata that indicates the presence of such
gases; or
(iii) The underground construction operation is both connected to
an underground work area which is currently classified as gassy and
is also subject to a continuous course of air containing the flammable
gas concentration.
(c) Declassification to potentially gassy operations. Underground construction
gassy operations may be declassified to potentially gassy when air monitoring
results remain under 10 percent of the lower explosive limit for methane
or other flammable gases for three consecutive days.
(12) Gassy operations-Additional requirements. Only acceptable equipment,
maintained in suitable condition, shall be used in gassy operations.
(a) Mobile diesel-powered equipment used in gassy operations shall
be either approved in accordance with the requirements of 30 CFR Part
36 (formerly Schedule 31) by MSHA, or shall be demonstrated by the employer
to be fully equivalent to such MSHA-approved equipment, and shall be
operated in accordance with that part.
(b) Each entrance to a gassy operation shall be prominently posted
with signs notifying all entrants of the gassy classification.
(c) Smoking shall be prohibited in all gassy operations and the employer
shall be responsible for collecting all personal sources of ignition,
such as matches and lighters, from all persons entering a gassy operation.
(d) A fire watch as described in chapter
296-155 WAC, Part H, shall be maintained when hot work is
performed.
(e) Once an operation has met the criteria in subsection (11)(a)(i)
of this section, warranting classification as gassy, all operations
in the affected area, except the following, shall be discontinued until
the operation either is in compliance with all of the gassy operation
requirements or has been declassified in accordance with (c) of this
subsection:
(i) Operations related to the control of the gas concentration;
(ii) Installation of new equipment, or conversion of existing equipment,
to comply with this subsection; and
(iii) Installation of above-ground controls for reversing the air
flow.
(13) Air quality and monitoring.
(a) General. Air quality limits and control requirements specified
in chapter
296-841 WAC shall apply except as modified by this subsection.
(b) The employer shall assign a competent person who shall perform
all air monitoring required by this section.
(c) Where this section requires monitoring of airborne contaminants
“as often as necessary,” the competent person shall make a reasonable
determination as to which substances to monitor and how frequently to
monitor, considering at least the following factors:
(i) Location of jobsite: Proximity to fuel tanks, sewers, gas lines,
old landfills, coal deposits, and swamps;
(ii) Geology: Geological studies of the jobsite, particularly involving
the soil type and its permeability;
(iii) History: Presence of air contaminants in nearby jobsites, changes
in levels of substances monitored on the prior shift; and
(iv) Work practices and jobsite conditions: The use of diesel engines,
use of explosives, use of fuel gas, volume and flow of ventilation,
visible atmospheric conditions, decompression of the atmosphere, welding,
cutting and hot work, and employees' physical reactions to working
underground.
(d) The employer shall provide testing and monitoring instruments which
are capable of achieving compliance with the provisions of this subsection,
and:
(i) Shall maintain the testing and monitoring instruments in good
condition;
(ii) Shall calibrate the instruments on a frequency not to exceed
6 months.
(e) Exposure to airborne contaminants shall not exceed the
levels established by chapter 296-841
WAC.
(f) Respirators shall not be substituted for environmental
control measures. However, where environmental controls have
not yet been developed, or when necessary by the nature of the
work involved (for example, welding, sand blasting, lead burning),
an employee may work for short periods of time in concentrations
of airborne contaminants which exceed the limit of permissible
exposure referred to in (d) of this subsection, if the employee
wears a respiratory protective device certified by MSHA-NIOSH
for protection against the particular hazards involved, and
the selection and use of respirators complies with the provisions
of chapter 296-842
WAC.
(g) Employees shall be withdrawn from areas in which there is a concentration
of an airborne contaminant which exceeds the permissible exposure limit
listed for that contaminant, except as modified in (t)(i) and (ii) of
this subsection.
(h) The atmosphere in all underground work areas shall be tested as
often as necessary to assure that the atmosphere at normal atmospheric
pressure contains at least 19.5 percent oxygen and no more than 22 percent
oxygen.
(i) Tests for oxygen content shall be made before tests for air contaminants.
(j) Field-type oxygen analyzers, or other suitable devices, shall be
used to test for oxygen deficiency.
(k) The atmosphere in all underground work areas shall be tested quantitatively
for carbon monoxide, nitrogen dioxide, hydrogen sulfide, and
other toxic gases, dust, vapors, mists, and fumes as often as
necessary to ensure that the permissible exposure limits prescribed
in chapter
296-62 WAC, Part H, are not exceeded.
(l) The atmosphere in all underground work areas shall be tested quantitatively
for methane and other flammable gases as often as necessary to determine:
(i) Whether action is to be taken under (q), (r), and (s) of this
subsection; and
(ii) Whether an operation is to be classified potentially gassy or
gassy under subsection (11) of this section.
(m) If diesel-engine or gasoline-engine driven ventilating fans or
compressors are used, an initial test shall be made of the inlet air
of the fan or compressor, with the engines operating, to ensure that
the air supply is not contaminated by engine exhaust.
(n) Testing shall be performed as often as necessary to ensure that
the ventilation requirements of subsection (15) of this section are
met.
(o) When rapid excavation machines are used, a continuous flammable
gas monitor shall be operated at the face with the sensor(s) placed
as high and close to the front of the machine's cutter head as practicable.
(p) Whenever air monitoring indicates the presence of 5 ppm or more
of hydrogen sulfide, a test shall be conducted in the affected underground
work area(s), at least at the beginning and midpoint of each shift,
until the concentration of hydrogen sulfide has been less than 5 ppm
for 3 consecutive days.
(i) Whenever hydrogen sulfide is detected in an amount exceeding
10 ppm, a continuous sampling and indicating hydrogen sulfide monitor
shall be used to monitor the affected work area.
(ii) Employees shall be informed when a concentration of 10 ppm hydrogen
sulfide is exceeded.
(iii) The continuous sampling and indicating hydrogen sulfide monitor
shall be designed, installed, and maintained to provide a visual and
aural alarm when the hydrogen sulfide concentration reaches 15 ppm
to signal that additional measures, such as respirator use, increased
ventilation, or evacuation, might be necessary to maintain hydrogen
sulfide exposure below the permissible exposure limit.
(q) When the competent person determines, on the basis of air monitoring
results or other information, that air contaminants may be present in
sufficient quantity to be dangerous to life, the employer shall:
(i) Prominently post a notice at all entrances to the underground
jobsite to inform all entrants of the hazardous condition; and
(ii) Immediately increase sampling frequency levels to insure workers
are not exposed to identified contaminants in excess of the permissible
exposure limit(s); and
(iii) Ensure that all necessary precautions are taken to comply with
pertinent requirements of this section, and chapter
296-62 WAC.
(r) Whenever five percent or more of the lower explosive limit for
methane or other flammable gases is detected in any underground work
area(s) or in the air return, steps shall be taken to increase ventilation
air volume or otherwise control the gas concentration, unless the employer
is operating in accordance with the potentially gassy or gassy operation
requirements. Such additional ventilation controls may be discontinued
when gas concentrations are reduced below five percent of the lower
explosive limit, but shall be reinstituted whenever the five percent
level is exceeded.
(s) Whenever 10 percent or more of the lower explosive limit for methane
or other flammable gases is detected in the vicinity of welding, cutting,
or other hot work, such work shall be suspended until the concentration
of such flammable gas is reduced to less than 10 percent of the lower
explosive limit.
(t) Whenever 20 percent or more of the lower explosive limit for methane
or other flammable gases is detected in any underground work area(s)
or in the air return:
(i) All employees, except those necessary to eliminate the hazard,
shall be immediately withdrawn to a safe location above ground; and
(ii) Employees who remain underground to correct or eliminate the
hazard described in (t) above shall be equipped with approved, pressure
demand mode, self-contained breathing apparatus, and shall have received
adequate training in the proper use of that equipment.
(iii) Electrical power, except for acceptable pumping and ventilation
equipment, shall be cut off to the area endangered by the flammable
gas until the concentration of such gas is reduced to less than 20
percent of the lower explosive limit.
(14) Additional monitoring for potentially gassy and gassy operations.
Operations which meet the criteria for potentially gassy and gassy operations
set forth in subsection (13) of this section shall be subject to the additional
monitoring requirements of this subsection.
(a) A test for oxygen content shall be conducted in the affected underground
work areas and work areas immediately adjacent to such areas at least
at the beginning and midpoint of each shift.
(b) When using rapid excavation machines, continuous automatic flammable
gas monitoring equipment shall be used to monitor the air at the heading,
on the rib, and in the return air duct. The continuous monitor shall
signal the heading, and shut down electric power in the affected underground
work area, except for acceptable pumping and ventilation equipment,
when 20 percent or more of the lower explosive limit for methane or
other flammable gases is encountered.
(i) A manual flammable gas monitor shall be used as needed, but at
least at the beginning and midpoint of each shift, to ensure that
the limits prescribed in subsections (11) and (13) of this section
are not exceeded. In addition, a manual electrical shut down control
shall be provided near the heading.
(ii) Local gas tests shall be made prior to and continuously during
any welding, cutting, or other hot work.
(iii) In underground operations driven by drill-and-blast methods,
the air in the affected area shall be tested for flammable gas prior
to re-entry after blasting, and continuously when employees are working
underground.
(c) Recordkeeping. A record of all air quality tests shall be maintained
above ground at the worksite and be made available to the director
or his/her representatives upon request. The record shall include
the location, date, time, substance and amount monitored. Records
of exposures to toxic substances shall be retained in accordance
with Part B, chapter
296-62 WAC. All other air quality test records shall be
retained until completion of the project.
(15) Ventilation.
(a) (i) Fresh air shall be supplied to all underground work areas
in sufficient quantities to prevent dangerous or harmful accumulation
of dust, fumes, mists, vapors, or gases.
(ii) Mechanical ventilation shall be provided in all underground
work areas except when the employer can demonstrate that natural ventilation
provides the necessary air quality through sufficient air volume and
air flow.
(b) A minimum of 200 cubic feet (5.7 m3) of fresh air per minute shall
be supplied for each employee underground.
(c) The linear velocity of air flow in the tunnel bore, in shafts,
and in all other underground work areas shall be at least 30 feet (9.15
m) per minute where blasting or rock drilling is conducted, or where
other conditions likely to produce dust, fumes, mists, vapors, or gases
in harmful or explosive quantities are present.
(d) The direction of mechanical air flow shall be reversible.
(e) Air that has passed through underground oil or fuel-storage areas
shall not be used to ventilate working areas.
(f) Following blasting, ventilation systems shall exhaust smoke and
fumes to the outside atmosphere before work is resumed in affected areas.
(g) Ventilation doors shall be designed and installed so that they
remain closed when in use, regardless of the direction of the air flow.
(h) When ventilation has been reduced to the extent that hazardous
levels of methane or flammable gas may have accumulated, a competent
person shall test all affected areas after ventilation has been restored
and shall determine whether the atmosphere is within flammable limits
before any power, other than for acceptable equipment, is restored or
work is resumed.
(i) Whenever the ventilation system has been shut down with all employees
out of the underground area, only competent persons authorized to test
for air contaminants shall be allowed underground until the ventilation
has been restored and all affected areas have been tested for air contaminants
and declared safe.
(j) When drilling rock or concrete, appropriate dust control measures
shall be taken to maintain dust levels within limits set in
chapter
296-155 WAC, Part B-1. Such measures may include, but are
not limited to, wet drilling, the use of vacuum collectors,
and water mix spray systems.
(k) (i) Internal combustion engines, except diesel-powered engines
on mobile equipment, are prohibited underground.
(ii) Mobile diesel-powered equipment used underground in atmospheres
other than gassy operations shall be either approved by MSHA in accordance
with the provisions of 30 CFR Part 32 (formerly Schedule 24), or shall
be demonstrated by the employer to be fully equivalent to such MSHA-approved
equipment, and shall be operated in accordance with that Part. (Each
brake horsepower of a diesel engine requires at least 100 cubic feet
(28.32 m3) of air per minute for suitable operation in addition to
the air requirements for personnel. Some engines may require a greater
amount of air to ensure that the allowable levels of carbon monoxide,
nitric oxide, and nitrogen dioxide are not exceeded.)
(iii) Application shall be made to the mining/explosives section,
department of labor and industries, for permission to use specified
diesel equipment in a specified underground area and shall include
the following:
(A) The type of construction and complete identification data and
specifications including analysis of the undiluted exhaust gases
of the diesel equipment.
(B) The location where the diesel equipment is to be used.
(C) Before the diesel equipment is taken underground, written permission
shall be obtained from the department of labor and industries or
its duly authorized representative. A satisfactory test on surface,
to show that the exhaust gases do not exceed the maximum percentage
of carbon monoxide permitted, shall be required.
(D) Diesel equipment shall only be used underground where the ventilation
is controlled by mechanical means and shall not be operated if the
ventilating current is less than 100 CFM per horsepower based on
the maximum brake horsepower of the engines.
(E) Air measurements shall be made at least once daily in the diesel
engine working area and the measurements entered in the Underground
Diesel Engine Record Book. Permissible maximum amounts of noxious
gases are as follows:
At engine exhaust ports
Carbon Monoxide
.10%
1,000 pm3
Next to equipment
Carbon Monoxide
.0035%
35 ppm
General atmosphere
Carbon Monoxide
.0035%
35 ppm
General atmosphere
Nitrogen Dioxide
.0001%
1 ppm
General atmosphere
Aldehydes
.0002%
2 ppm
3Parts of vapor or gas per million parts of contaminated air
by volume at 25°C and 760 mm Hg. pressure.
(l) Potentially gassy or gassy operations shall have ventilation systems
installed which shall:
(i) Be constructed of fire-resistant materials; and
(ii) Have acceptable electrical systems, including fan motors.
(m) Gassy operations shall be provided with controls located aboveground
for reversing the air flow of ventilation systems.
(n) In potentially gassy or gassy operations, wherever mine-type ventilation
systems using an offset main fan installed on the surface are used,
they shall be equipped with explosion-doors or a weak-wall having an
area at least equivalent to the cross-sectional area of the airway.
(16) Illumination.
(a) Sufficient lighting shall be provided, in accordance with the requirements
of chapter
296-155 WAC, Part B-1, to permit safe operations at the
face as well as in the general tunnel or shaft area and at the
employees' workplace.
(b) Only acceptable portable lighting shall be used within 50 feet
(15.24 m) of any underground heading during explosive handling.
(17) Fire prevention and control. Fire prevention and protection requirements
applicable to underground construction operations are found in Part D
of this chapter except as modified by the following additional standards.
(a) Open flames and fires are prohibited in all underground construction
operations except as permitted for welding, cutting, and other hot work
operations.
(i) Smoking may be allowed only in areas free of fire and explosion
hazards.
(ii) Readily visible signs prohibiting smoking and open flames shall
be posted in areas having fire or explosion hazards.
(iii) The carrying of matches, lighters, or other flame-producing
smoking materials shall be prohibited in all underground operations
where fire or explosion hazards exist.
(b) The employer may store underground no more than a 24-hour supply
of diesel fuel for the underground equipment used at the worksite.
(c) The piping of diesel fuel from the surface to an underground location
is permitted only if:
(i) Diesel fuel is contained at the surface in a tank whose maximum
capacity is no more than the amount of fuel required to supply for
a 24-hour period the equipment serviced by the underground fueling
station; and
(ii) The surface tank is connected to the underground fueling station
by an acceptable pipe or hose system that is controlled at the surface
by a valve, and at the shaft bottom by a hose nozzle; and
(iii) The pipe is empty at all times except when transferring diesel
fuel from the surface tank to a piece of equipment in use underground;
and
(iv) Hoisting operations in the shaft are suspended during refueling
operations if the supply piping in the shaft is not protected from
damage.
(d) (i) Gasoline shall not be carried, stored, or used underground.
(ii) Acetylene, liquefied petroleum gas, and methylacetylene propadiene
stabilized gas may be used underground only for welding, cutting and
other hot work, and only in accordance with Part H of this chapter
and subsections (13), (15), (17), and (18) of this section.
(e) Oil, grease, and diesel fuel stored underground shall be kept in
tightly sealed containers in fire-resistant areas at least 300 feet
(91.44 m) from underground explosive magazines, and at least 100 feet
(30.48 m) from shaft stations and steeply inclined passageways. Storage
areas shall be positioned or diked so that the contents of ruptured
or overturned containers will not flow from the storage area.
(f) Flammable or combustible materials shall not be stored above ground
within 100 feet (30.48 m) of any access opening to any underground operation.
Where this is not feasible because of space limitations at the jobsite,
such materials may be located within the 100-foot limit, provided that:
(i) They are located as far as practicable from the opening; and
(ii) Either a fire-resistant barrier of not less than one-hour rating
is placed between the stored material and the opening, or additional
precautions are taken which will protect the materials from ignition
sources.
(g) Fire-resistant hydraulic fluids shall be used in hydraulically-actuated
underground machinery and equipment unless such equipment is protected
by a fire suppression system or by multipurpose fire extinguisher(s)
rated at a sufficient capacity for the type and size of hydraulic equipment
involved, but rated at least 4A:4OB:C.
(h) (i) Electrical installations in underground areas where oil,
grease, or diesel fuel are stored shall be used only for lighting
fixtures.
(ii) Lighting fixtures in storage areas, or within 25 feet (7.62
m) of underground areas where oil, grease, or diesel fuel are stored,
shall be approved for Class I, Division 2 locations, in accordance
with Part I of this chapter.
(i) Leaks and spills of flammable or combustible fluids shall be cleaned
up immediately.
(j) A fire extinguisher of at least 4A:4OB:C rating or other equivalent
extinguishing means shall be provided at the head pulley and at the
tail pulley of underground belt conveyors, and at 300-foot intervals
along the belt.
(k) Any structure located underground or within 100 feet (30.48 m)
of an opening to the underground shall be constructed of material having
a fire-resistance rating of at least one hour.
(18) Welding, cutting, and other hot work. In addition to the requirements
of Part H of this chapter, the following requirements shall apply to underground
welding, cutting, and other hot work.
(a) No more than the amount of fuel gas and oxygen cylinders necessary
to perform welding, cutting, or other hot work during the next 24-hour
period shall be permitted underground.
(b) Noncombustible barriers shall be installed below welding, cutting,
or other hot work being done in or over a shaft or raise.
(19) Ground support.
(a) In tunnels (other than hard rock) timber sets, steel rings, steel
frames, concrete liners, or other engineered tunnel support systems
shall be used. Every tunnel support system shall be designed by a licensed
professional engineer. Design specifications shall be available at the
worksite.
(b) Portal areas. Portal openings and access areas shall be guarded
by shoring, fencing, head walls, shotcreting, or other equivalent protection
to ensure safe access of employees and equipment. Adjacent areas shall
be scaled or otherwise secured to prevent loose soil, rock, or fractured
materials from endangering the portal and access area.
(c) Subsidence areas. The employer shall ensure ground stability in
hazardous subsidence areas by shoring, by filling in, or by erecting
barricades and posting warning signs to prevent entry.
(d) Underground areas.
(i) (A) A competent person shall inspect the roof, face, and walls
of the work area at the start of each shift and as often as necessary
to determine ground stability.
(B) Competent persons conducting such inspections shall be protected
from loose ground by location, ground support, or equivalent means.
(ii) Ground conditions along haulageways and travelways shall be
inspected as frequently as necessary to ensure safe passage.
(iii) Loose ground that might be hazardous to employees shall be
taken down, scaled, or supported.
(iv) Torque wrenches shall be used wherever bolts that depend on
torsionally applied force are used for ground support.
(v) A competent person shall determine whether rock bolts meet the
necessary torque, and shall determine the testing frequency in light
of the bolt system, ground conditions, and the distance from vibration
sources.
(vi) Suitable protection shall be provided for employees exposed
to the hazard of loose ground while installing ground support systems.
(vii) Support sets shall be installed so that the bottoms have sufficient
anchorage to prevent ground pressures from dislodging the support
base of the sets. Lateral bracing (collar bracing, tie rods, or spreaders)
shall be provided between immediately adjacent sets to ensure added
stability.
(viii) Damaged or dislodged ground supports that create a hazardous
condition shall be promptly repaired or replaced. When replacing supports,
the new supports shall be installed before the damaged supports are
removed.
(ix) A shield or other type of support shall be used to maintain
a safe travelway for employees working in dead-end areas ahead of
any support replacement operation.
(e) Shafts.
(i) Shafts and wells over 4 feet (1.219 m) in depth that employees
must enter shall be supported by a steel casing, concrete pipe, timber,
solid rock, or other suitable material.
(ii) (A) The full depth of the shaft shall be supported by casing
or bracing except where the shaft penetrates into solid rock having
characteristics that will not change as a result of exposure. Where
the shaft passes through earth into solid rock, or through solid
rock into earth, and where there is potential for shear, the casing
or bracing shall extend at least 5 feet (1.53 m) into the solid
rock. When the shaft terminates in solid rock, the casing or bracing
shall extend to the end of the shaft or 5 feet (1.53 m) into the
solid rock, whichever is less.
(B) The casing or bracing shall extend 42 inches (1.07 m) plus
or minus 3 inches (8 cm) above ground level, except that the minimum
casing height may be reduced to 12 inches (0.3 m), provided that
a standard railing is installed; that the ground adjacent to the
top of the shaft is sloped away from the shaft collar to prevent
entry of liquids; and that effective barriers are used to prevent
mobile equipment operating near the shaft from jumping over the
12-inch (0.3 m) barrier.
(iii) After blasting operations in shafts, a competent person shall
determine if the walls, ladders, timbers, blocking, or wedges have
loosened. If so, necessary repairs shall be made before employees
other than those assigned to make the repairs are allowed in or below
the affected areas.
(f) Blasting. This subsection applies in addition to the requirements
for blasting and explosives operations, including handling of
misfires, which are found in chapter
296-52 WAC.
(i) Blasting wires shall be kept clear of electrical lines, pipes,
rails, and other conductive material, excluding earth, to prevent
explosives initiation or employee exposure to electric current.
(ii) Following blasting, an employee shall not enter a work area
until the air quality meets the requirements of subsection (13) of
this section.
(g) Drilling.
(i) A competent person shall inspect all drilling and associated
equipment prior to each use. Equipment defects affecting safety shall
be corrected before the equipment is used.
(ii) The drilling area shall be inspected for hazards before the
drilling operation is started.
(iii) Employees shall not be allowed on a drill mast while the drill
bit is in operation or the drill machine is being moved.
(iv) When a drill machine is being moved from one drilling area to
another, drill steel, tools, and other equipment shall be secured
and the mast shall be placed in a safe position.
(v) Receptacles or racks shall be provided for storing drill steel
located on jumbos.
(vi) Employees working below jumbo decks shall be warned whenever
drilling is about to begin.
(vii) Drills on columns shall be anchored firmly before starting
drilling, and shall be retightened as necessary thereafter.
(viii) The employer shall provide mechanical means on the top deck
of a jumbo for lifting unwieldy or heavy material.
(ix) When jumbo decks are over 10 feet (3.05 m) in height, the employer
shall install stairs wide enough for two persons.
(x) Jumbo decks more than 10 feet (3.05 m) in height shall be equipped
with guardrails on all open sides, excluding access openings of platforms,
unless an adjacent surface provides equivalent fall protection.
(xi) Only employees assisting the operator shall be allowed to ride
on jumbos, unless the jumbo meets the requirements of subsection (20)(e)
of this section.
(xii) Jumbos shall be chocked to prevent movement while employees
are working on them.
(xiii) Walking and working surfaces of jumbos shall be maintained
to prevent the hazards of slipping, tripping, and falling.
(xiv) Jumbo decks and stair treads shall be designed to be slip-resistant
and secured to prevent accidental displacement.
(xv) Scaling bars shall be available at scaling operations and shall
be maintained in good condition at all times. Blunted or severely
worn bars shall not be used.
(xvi) Before commencing the drill cycle, the face and lifters shall
be examined for misfires (residual explosives) and, if found, they
shall be removed before drilling commences at the face. Blasting holes
shall not be drilled through blasted rock (muck) or water.
(xvii) Employees in a shaft shall be protected either by location
or by suitable barrier(s) if powered mechanical loading equipment
is used to remove muck containing unfired explosives.
(xviii) A caution sign reading “buried line,” or similar wording
shall be posted where air lines are buried or otherwise hidden by
water or debris.
(20) Haulage.
(a) A competent person shall inspect haulage equipment before each
shift.
(i) Equipment defects affecting safety and health shall be corrected
before the equipment is used.
(ii) Powered mobile haulage equipment shall be provided with adequate
brakes.
(iii) Power mobile haulage equipment, including trains, shall have
audible warning devices to warn employees to stay clear. The operator
shall sound the warning device before moving the equipment and whenever
necessary during travel.
(iv) The operator shall assure that lights which are visible to employees
at both ends of any mobile equipment, including a train, are turned
on whenever the equipment is operating.
(v) In those cabs where glazing is used, the glass shall be safety
glass, or its equivalent, and shall be maintained and cleaned so that
vision is not obstructed.
(b) Antirollback devices or brakes shall be installed on inclined conveyor
drive units to prevent conveyors from inadvertently running in reverse.
Employees shall not be permitted to ride a power-driven chain, belt,
or bucket conveyor unless the conveyor is specifically designed for
the transportation of persons.
(c) Endless belt-type manlifts are prohibited in underground construction.
(d) General requirements also applicable to underground construction
for use of conveyors in construction are found in chapter
296-155 WAC, Part L.
(e) No employee shall ride haulage equipment unless it is equipped
with seating for each passenger and protects passengers from
being struck, crushed, or caught between other equipment or
surfaces. Members of train crews may ride on a locomotive if
it is equipped with handholds and nonslip steps or footboards.
Requirements applicable to underground construction for motor
vehicle transportation of employees are found in chapter
296-155 WAC, Part M.
(f) Conveyor lockout.
(i) Conveyors shall be de-energized and locked out with a padlock,
and tagged out with a “Do Not Operate” tag at any time repair, maintenance,
or clean-up work is being performed on the conveyor.
(ii) Tags or push button stops are not acceptable.
(iii) Persons shall not be allowed to walk on conveyors except for
emergency purposes and then only after the conveyor has been deenergized
and locked out in accordance with (f) above, and persons can do so
safely.
(g) Powered mobile haulage equipment, including trains, shall not be
left unattended unless the master switch or motor is turned off; operating
controls are in neutral or park position; and the brakes are set, or
equivalent precautions are taken to prevent rolling.
(h) Whenever rails serve as a return for a trolley circuit, both rails
shall be bonded at every joint and crossbonded every 200 feet (60.96
m).
(i) When dumping cars by hand, the car dumps shall have tiedown chains,
bumper blocks, or other locking or holding devices to prevent the cars
from overturning.
(j) Rocker-bottom or bottom-dump cars shall be equipped with positive
locking devices to prevent unintended dumping.
(k) Equipment to be hauled shall be loaded and secured to prevent sliding
or dislodgment.
(l) (i) Mobile equipment, including rail-mounted equipment, shall
be stopped for manual connecting or service work, and;
(ii) Employees shall not reach between moving cars during coupling
operations.
(iii) Couplings shall not be aligned, shifted, or cleaned on moving
cars or locomotives.
(iv) Safety chains or other connections shall be used in addition
to couplers to connect person cars or powder cars whenever the locomotive
is uphill of the cars.
(v) When the grade exceeds one percent and there is a potential for
runaway cars, safety chains or other connections shall be used in
addition to couplers to connect haulage cars or, as an alternative,
the locomotive must be downhill of the train.
(vi) Such safety chains or other connections shall be capable of
maintaining connection between cars in the event of either coupler
disconnect, failure or breakage.
(m) Parked rail equipment shall be chocked, blocked, or have brakes
set to prevent inadvertent movement.
(n) Berms, bumper blocks, safety hooks, or equivalent means shall be
provided to prevent overtravel and overturning of haulage equipment
at dumping locations.
(o) Bumper blocks or equivalent stopping devices shall be provided
at all track dead ends.
(p) (i) Only small handtools, lunch pails, or similar small items
may be transported with employees in person cars, or on top of a locomotive.
(ii) When small hand tools or other small items are carried on top
of a locomotive, the top shall be designed or modified to retain them
while traveling.
(q) (i) Where switching facilities are available, occupied personnel
cars shall be pulled, not pushed. If personnel cars must be pushed
and visibility of the track ahead is hampered, then a qualified person
shall be stationed in the lead car to give signals to the locomotive
operator.
(ii) Crew trips shall consist of personnel loads only.
(21) Electrical safety. This subsection applies in addition to the general
requirements for electrical safety which are found in Part I of this chapter.
(a) Electric power lines shall be insulated or located away from water
lines, telephone lines, air lines, or other conductive materials so
that a damaged circuit will not energize the other systems.
(b) Lighting circuits shall be located so that movement of personnel
or equipment will not damage the circuits or disrupt service.
(c) Oil-filled transformers shall not be used underground unless they
are located in a fire-resistant enclosure suitably vented to the outside
and surrounded by a dike to retain the contents of the transformers
in the event of rupture.
(22) Hoisting unique to underground construction except as modified
by this section, the following provisions of chapter
296-155 WAC, Part L apply: Requirements for cranes are found
in WAC
296-155-525. WAC
296-155-528 contains rules applicable to crane hoisting of
personnel, except, that the limitations imposed by WAC
296-155-528(2) do not apply to the routine access of employees
to the underground via a shaft. Requirements for personnel hoists,
material hoists, and elevators are found in WAC
296-155-530 and in this subsection.
(a) General requirements for cranes and hoists.
(i) Materials, tools, and supplies being raised or lowered, whether
within a cage or otherwise, shall be secured or stacked in a manner
to prevent the load from shifting, snagging, or falling into the shaft.
(ii) A warning light suitably located to warn employees at the shaft
bottom and subsurface shaft entrances shall flash whenever a load
is above the shaft bottom or subsurface entrances, or the load is
being moved in the shaft. This subsection does not apply to fully
enclosed hoistways.
(iii) Whenever a hoistway is not fully enclosed and employees are
at the shaft bottom, conveyances or equipment shall be stopped at
least 15 feet (4.57 m) above the bottom of the shaft and held there
until the signalperson at the bottom of the shaft directs the operator
to continue lowering the load, except that the load may be lowered
without stopping if the load or conveyance is within full view of
a bottom signalperson who is in constant voice communication with
the operator.
(iv) (A) Before maintenance, repairs, or other work is commenced
in the shaft served by a cage, skip, or bucket, the operator and
other employees in the area shall be informed and given suitable
instructions.
(B) A sign warning that work is being done in the shaft shall be
installed at the shaft collar, at the operator's station, and at
each underground landing.
(v) Any connection between the hoisting rope and the cage or skip
shall be compatible with the type of wire rope used for hoisting.
(vi) Spin-type connections, where used, shall be maintained in a
clean condition and protected from foreign matter that could affect
their operation.
(vii) Cage, skip, and load connections to the hoist rope shall be
made so that the force of the hoist pull, vibration, misalignment,
release of lift force, or impact will not disengage the connection.
Only closed shackles shall be used for cage and skip rigging.
(viii) When using wire rope wedge sockets, means shall be provided
to prevent wedge escapement and to ensure that the wedge is properly
seated.
(b) Additional requirements for cranes. Cranes shall be equipped with
a limit switch to prevent overtravel at the boom tip. Limit switches
are to be used only to limit travel of loads when operational controls
malfunction and shall not be used as a substitute for other operational
controls.
(c) Additional requirements for hoists.
(i) Hoists shall be designed so that the load hoist drum is powered
in both directions of rotation, and so that brakes are automatically
applied upon power release or failure.
(ii) Control levers shall be of the “deadman type” which return automatically
to their center (neutral) position upon release.
(iii) When a hoist is used for both personnel hoisting and material
hoisting, load and speed ratings for personnel and for materials shall
be assigned to the equipment.
(iv) Hoist machines with cast metal parts shall not be used.
(v) Material hoisting may be performed at speeds higher than the
rated speed for personnel hoisting if the hoist and components have
been designed for such higher speeds and if shaft conditions permit.
(vi) Employees shall not ride on top of any cage, skip, or bucket
except when necessary to perform inspection or maintenance of the
hoisting system, in which case they shall be protected by a body belt/harness
system to prevent falling.
(vii) Personnel and materials (other than small tools and supplies
secured in a manner that will not create a hazard to employees) shall
not be hoisted together in the same conveyance. However, if the operator
is protected from the shifting of materials, then the operator may
ride with materials in cages or skips which are designed to be controlled
by an operator within the cage or skip.
(viii) Line speed shall not exceed the design limitations of the
systems.
(ix) Hoists shall be equipped with landing level indicators at the
operator's station. Marking of the hoist rope does not satisfy this
requirement.
(x) Whenever glazing is used in the hoist house, it shall be safety
glass, or its equivalent, and be free of distortions and obstructions.
(xi) A fire extinguisher that is rated at least 2A:10B:C (multipurpose,
dry chemical) shall be mounted in each hoist house.
Note: For additional requirements relating to portable
fire extinguishers see WAC
296-800-300.
(xii) Hoist controls shall be arranged so that the operator can perform
all operating cycle functions and reach the emergency power cutoff
without having to reach beyond the operator's normal operating position.
(xiii) Hoists shall be equipped with limit switches to prevent overtravel
at the top and bottom of the hoistway.
(xiv) Limit switches are to be used only to limit travel of loads
when operational controls malfunction and shall not be used as a substitute
for other operational controls.
(xv) Hoist operators shall be provided with a closed-circuit voice
communication system to each landing station, with speaker-microphones
so located that the operator can communicate with individual landing
stations during hoist use.
(xvi) When sinking shafts 75 feet (22.86 m) or less in depth, cages,
skips, and buckets that may swing, bump, or snag against shaft sides
or other structural protrusions shall be guided by fenders, rails,
ropes, or a combination of those means.
(xvii) When sinking shafts more than 75 feet (22.86 m) in depth,
all cages, skips, and buckets shall be rope or rail-guided to within
a rail length from the sinking operation.
(xviii) Cages, skips, and buckets in all completed shafts, or in
all shafts being used as completed shafts, shall be rope or rail-guided
for the full length of their travel.
(xix) Wire rope used in load lines of material hoists shall be capable
of supporting, without failure, at least five times the maximum
intended load or the factor recommended by the rope manufacturer,
whichever is greater. Refer to chapter
296-155 WAC, Part L, for design factors for wire rope
used in personnel hoists. The design factors shall be calculated
by dividing the breaking strength of wire rope, as reported
in the manufacturer's rating tables, by the total static load,
including the weight of the wire rope in the shaft when fully
extended.
(xx) A competent person shall visually check all hoisting machinery,
equipment, anchorages, and hoisting rope at the beginning of each
shift and during hoist use, as necessary.
(xxi) Each safety device shall be checked by a competent person at
least weekly during hoist use to ensure suitable operation and safe
condition.
(xxii) In order to ensure suitable operation and safe condition of
all functions and safety devices, each hoist assembly shall be inspected
and load-tested to 100 percent of its rated capacity: At the time
of installation; after any repairs or alterations affecting its structural
integrity; after the operation of any safety device; and annually
when in use. The employer shall prepare a certification record which
includes the date each inspection and load-test was performed; the
signature of the person who performed the inspection and test; and
a serial number or other identifier for the hoist that was inspected
and tested. The most recent certification record shall be maintained
on file until completion of the project.
(xxiii) Before hoisting personnel or material, the operator shall
perform a test run of any cage or skip whenever it has been out of
service for one complete shift, and whenever the assembly or components
have been repaired or adjusted.
(xiv) Unsafe conditions shall be corrected before using the equipment.
(d) Additional requirements for personnel hoists.
(i) Hoist drum systems shall be equipped with at least two means
of stopping the load, each of which shall be capable of stopping and
holding 150 percent of the hoist's rated line pull. A broken-rope
safety, safety catch, or arrestment device is not a permissible means
of stopping under this subsection.
(ii) The operator shall remain within sight and sound of the signals
at the operator's station.
(iii) All sides of personnel cages shall be enclosed by one-half
inch (12.70 mm) wire mesh (not less than No. 14 gauge or equivalent)
to a height of not less than 6 feet (1.83 m). However, when the cage
or skip is being used as a work platform, its sides may be reduced
in height to 42 inches (1.07 m) when the conveyance is not in motion.
(iv) All personnel cages shall be provided with a positive locking
door that does not open outward.
(v) All personnel cages shall be provided with a protective canopy.
The canopy shall be made of steel plate, at least 3/16 -inch (4.763
mm) in thickness, or material of equivalent strength and impact resistance.
The canopy shall be sloped to the outside, and so designed that a
section may be readily pushed upward to afford emergency egress. The
canopy shall cover the top in such a manner as to protect those inside
from objects falling in the shaft.
(vi) Personnel platforms operating on guide rails or guide ropes
shall be equipped with broken-rope safety devices, safety catches,
or arrestment devices that will stop and hold 150 percent of the weight
of the personnel platform and its maximum rated load.
(vii) During sinking operations in shafts where guides and safeties
are not yet used, the travel speed of the personnel platform shall
not exceed 200 feet (60.96 m) per minute. Governor controls set for
200 feet (60.96 m) per minute shall be installed in the control system
and shall be used during personnel hoisting.
(viii) The personnel platform may travel over the controlled length
of the hoistway at rated speeds up to 600 feet (182.88 m) per minute
during sinking operations in shafts where guides and safeties are
used.
(ix) The personnel platform may travel at rated speeds greater than
600 feet (182.88 m) per minute in complete shafts.
(1) Wherever, in caisson work in which compressed air is used, and the
working chamber is less than 11 feet in length, and when such caissons
are at any time suspended or hung while work is in progress so that the
bottom of the excavation is more than 9 feet below the deck of the working
chamber, a shield shall be erected therein for the protection of the employees.
(2) Shafts shall be subjected to a hydrostatic or airpressure test, at
which pressure they shall be tight. The shaft shall be stamped on the
outside shell about 12 inches from each flange to show the pressure to
which they have been subjected.
(3) Whenever a shaft is used, it shall be provided, where space permits,
with a safe, proper, and suitable staircase for its entire length, including
landing platforms, not more than 20 feet apart. Where this is impracticable,
suitable ladders shall be installed with landing platforms located about
20 feet apart to break the climb.
(4) All caissons, having a diameter or side greater than 10 feet shall
be provided with a man lock and shaft for the exclusive use of employees.
(5) In addition to the gauge in the locks, an accurate gauge shall be
maintained on the outer and inner side of each bulkhead. These gauges
shall be accessible at all times and kept in accurate working order.
(6) In caisson operations where employees are exposed to compressed air
working environments, the requirements contained in WAC
296-155-745 shall be complied with.
(1) If overtopping of the cofferdam by high waters is possible, means
shall be provided for controlled flooding of the work area.
(2) Warning signals for evacuation of employees in case of emergency
shall be developed and posted.
(3) Cofferdam walkways, bridges, or ramps with at least two means of
rapid exit, shall be provided with guardrails as specified in Part K of
this chapter.
(4) Manways and ladderways shall be installed separately from the hoistways
and partitioned off to prevent hoisted materials from protruding into
or falling into manways and/or ladderways.
(5) Pumping equipment shall be located on substantially constructed platforms
and where installed in such a position that persons must work below, toe
boards shall be installed on the platform.
(6) Cofferdams located close to navigable shipping channels shall be
protected from vessels in transit, where possible.
(a) There shall be present, at all times, at least one competent person
designated by and representing the employer, who shall be familiar with
this part in all respects and responsible for full compliance with these
and other applicable parts.
(b) Every employee shall be instructed in the rules and regulations
which concern their safety or the safety of others.
(2) Medical attendance, examination, and regulations.
(a) There shall be retained one or more licensed physicians familiar
with and experienced in the physical requirements and the medical aspects
of compressed air work and the treatment of decompression illness. They
shall be available at all times while work is in progress in order to
provide medical supervision of employees employed in compressed air
work. They shall be physically qualified and be willing to enter a pressurized
environment.
(b) No employee shall be permitted to enter a compressed air environment
until they have been examined by the physician and reported to be physically
qualified to engage in such work.
(c) In the event an employee is absent from work for 10 days, or is
absent due to sickness or injury, they shall not resume work until they
are reexamined by the physician, and their physical condition reported,
as provided in this subsection, to be such as to permit them to work
in compressed air.
(d) After an employee has been employed continuously in compressed
air for a period designated by the physician, but not to exceed 1 year,
the employee shall be reexamined by the physician to determine if they
are still physically qualified to engage in compressed air work.
(e) Such physician shall at all times keep a complete and full record
of examinations made by themselves. The physician shall also keep an
accurate record of any decompression illness or other illness or injury
incapacitating any employee for work, and of all loss of life that occurs
in the operation of a tunnel, caisson, or other compartment in which
compressed air is used.
(f) Records shall be available for the inspection by the director or
his/her representatives, and a copy thereof shall be forwarded to the
department within 48 hours following the occurrence of the accident,
death, injury, or decompression illness. It shall state as fully as
possible the cause of said death or decompression illness, and the place
where the injured or sick employee was taken, and such other relative
information as may be required by the director.
(g) A fully equipped first-aid station shall be provided at each tunnel
project regardless of the number of persons employed. An ambulance or
transportation suitable for a litter case shall be at each project.
(h) Where tunnels are being excavated from portals more than 5 road
miles apart, a first-aid station and transportation facilities shall
be provided at each portal.
(i) A medical lock shall be established and maintained in immediate
working order whenever air pressure in the working chamber is increased
above the normal atmosphere.
(j) The medical lock shall:
(i) Have at least 6 feet of clear headroom at the center, and be
subdivided into not less than two compartments;
(ii) Be readily accessible to employees working under compressed
air;
(iii) Be kept ready for immediate use for at least 5 hours subsequent
to the emergence of any employee from the working chamber;
(iv) Be properly heated, lighted and ventilated;
(v) Be maintained in a sanitary condition;
(vi) Have a nonshatterable port through which the occupant(s) may
be kept under constant observation;
(vii) Be designed for a working pressure of 75 p.s.i.g.;
(viii) Be equipped with internal controls which may be overridden
by external controls;
(ix) Be provided with air pressure gauges to show the air pressure
within each compartment to observers inside and outside the medical
lock;
(x) Be equipped with a manual type sprinkler system that can be activated
inside the lock or by the outside lock tender;
(xi) Be provided with oxygen lines and fittings leading into external
tanks. The lines shall be fitted with check valves to prevent reverse
flow. The oxygen system inside the chamber shall be of a closed circuit
design and be so designed as to automatically shut off the oxygen
supply whenever the fire system is activated.
(xii) Be in constant charge of an attendant under the direct control
of the retained physician. The attendant shall be trained in the use
of the lock and suitably instructed regarding steps to be taken in
the treatment of employee exhibiting symptoms compatible with a diagnosis
of decompression illness;
(xiii) Be adjacent to an adequate emergency medical facility;
(xiv) The medical facility shall be equipped with demand-type oxygen
inhalation equipment approved by the U.S. Bureau of Mines or Mine
Safety and Health Administration (MSHA) and the National Institute
for Occupational Safety and Health (NIOSH);
(xv) Be capable of being maintained at a temperature, in use, not
to exceed 90°F. nor be less than 70°F.; and
(xvi) Be provided with sources of air, free of oil and carbon monoxide,
for normal and emergency use, which are capable of raising the air
pressure in the lock from 0 to 75 p.s.i.g. in 5 minutes.
(k) Identification badges shall be furnished to all employees, indicating
that the wearer is a compressed air worker. A permanent record shall
be kept of all identification badges issued. The badge shall give the
employee's name, address of the medical lock, the telephone number of
the licensed physician for the compressed air project, and contain instructions
that in case of emergency of unknown or doubtful cause or illness, the
wearer shall be rushed to the medical lock. The badge shall be worn
at all times-off the job, as well as on the job.
(3) Telephone and signal communication. Effective and reliable means
of communication, such as bells, whistles, or telephones, shall be maintained
at all times between all the following locations;
(a) The working chamber face;
(b) The working chamber side of the man lock near the door;
(c) The interior of the man lock;
(d) Lock attendant's station;
(e) The compressor plant;
(f) The first-aid station;
(g) The emergency lock (if one is required); and
(h) The special decompression chamber (if one is required).
(4) Signs and records.
(a) The time of decompression shall be posted in each man lock as follows:
This form shall be posted in the man lock at all times.
(b) Any code of signals used shall be conspicuously posted near workplace
entrances and such other locations as may be necessary to bring them
to the attention of all employees concerned.
(c) For each 8-hour shift, a record of employees employed under air
pressure shall be kept by an employee who shall remain outside the lock
near the entrance. This record shall show the period each employee spends
in the air chamber and the time taken from decompression. A copy shall
be submitted to the appointed physician after each shift.
(5) Compression.
(a) Every employee going under air pressure for the first time shall
be instructed on how to avoid excessive discomfort.
(b) During the compression of employees, the pressure shall not be
increased to more than 3 p.s.i.g. within the first minute. The pressure
shall be held at 3 p.s.i.g. and again at 7 p.s.i.g. sufficiently long
to determine if any employees are experiencing discomfort.
(c) After the first minute the pressure shall be raised uniformly and
at a rate not to exceed 10 p.s.i. per minute.
(d) If any employee complains of discomfort, the pressure shall be
held to determine if the symptoms are relieved. If, after 5 minutes
the discomfort does not disappear, the lock attendant shall gradually
reduce the pressure until the employee signals that the discomfort has
ceased. If the employee does not indicate that the discomfort has disappeared,
the lock attendant shall reduce the pressure to atmospheric and the
employee shall be released from the lock.
(e) No employee shall be subjected to pressure exceeding 50 pounds
per square inch except in an emergency.
(6) Decompression.
(a) Decompression to normal condition shall be in accordance with the
decompression tables in Appendix A of this part.
(b) In the event it is necessary for an employee to be in compressed
air more than once in a 24-hour period, the appointed physician shall
be responsible for the establishment of methods and procedures of decompression
applicable to repetitive exposures.
(c) If decanting is necessary, the appointed physician shall establish
procedures before any employee is permitted to be decompressed by decanting
methods. The period of time that the employees spend at atmospheric
pressure between the decompression following the shift and recompression
shall not exceed 5 minutes.
(7) Man locks and special decompression chambers.
(a) Man locks.
(i) Except in emergency, no employees employed in compressed air
shall be permitted to pass from the working chamber to atmospheric
pressure until after decompression, in accordance with the procedures
in this part.
(ii) The lock attendant in charge of a man lock shall be under the
direct supervision of the appointed physician. The lock attendant
shall be stationed at the lock controls on the free air side during
the period of compression and decompression and shall remain at the
lock control station whenever there are persons in the working chamber
or in the man lock.
(iii) Except where air pressure in the working chamber is below 12
p.s.i.g., each man lock shall be equipped with automatic controls
which, through taped programs, cams, or similar apparatus, shall automatically
regulate decompressions. It shall also be equipped with manual controls
to permit the lock attendant to override the automatic mechanism in
the event of an emergency, as provided in item (viii) of this subdivision.
(iv) A manual control, which can be used in the event of an emergency,
shall be placed inside the man lock.
(v) A clock, thermometer, and continuous recording pressure gauge
with a 4-hour graph shall be installed outside of each man lock and
shall be changed prior to each shift's decompression. The chart shall
be of sufficient size to register a legible record of variations in
pressure within the man lock and shall be visible to the lock attendant.
A copy of each graph shall be submitted to the appointed physician
after each shift. In addition, a pressure gauge, clock, and thermometer
shall also be installed in each man lock. Additional fittings shall
be provided so that the test gauges may be attached whenever necessary.
(vi) Except where air pressure is below 12 p.s.i.g. and there is
no danger of rapid flooding, all caissons having a working area greater
than 150 square feet, and each bulkhead in tunnels of 14 feet or more
in diameter, or equivalent area, shall have at least two locks in
perfect working condition, one of which shall be used exclusively
as a man lock, the other, as a materials lock.
(vii) Where only a combination man-and-materials lock is required,
this single lock shall be of sufficient capacity to hold the employees
constituting two successive shifts.
(viii) Emergency locks shall be large enough to hold an entire heading
shift and a limit maintained of 12 p.s.i.g. There shall be a chamber
available for oxygen decompression therapy to 28 p.s.i.g.
(ix) The man lock shall be large enough so that those using it are
not compelled to be in a cramped position and shall not have less
than 5 feet clear head room at the center and a minimum of 30 cubic
feet of air space per occupant.
(x) Locks on caissons shall be so located that the bottom door shall
be not less than 3 feet above the water level surrounding the caisson
on the outside. (The water level, where it is affected by tides, is
construed to mean high tide.)
(xi) In addition to the pressure gauge in the locks, an accurate
pressure gauge shall be maintained on the outer and inner side of
each bulkhead. These gauges shall be accessible at all times and shall
be kept in accurate working order.
(xii) Man locks shall have an observation port at least 4 inches
in diameter located in such a position that all occupants of the man
lock may be observed from the working chamber and from the free air
side of the lock.
(xiii) Adequate ventilation in the lock shall be provided.
(xiv) Man locks shall be maintained at a minimum temperature of 70°F.
(xv) When locks are not in use and employees are in the working chamber,
lock doors shall be kept open to the working chamber, where practicable.
(xvi) Provision shall be made to allow for rescue parties to enter
the tunnel if the working force is disabled.
(xvii) A special decompression chamber of sufficient size to accommodate
the entire force of employees being decompressed at the end of a shift
shall be provided whenever the regularly established working period
requires total time of decompression exceeding 75 minutes.
(b) Special decompression chamber.
(i) The headroom in the special decompression chamber shall be not
less than a minimum 7 feet and the cubical content shall provide at
least 50 cubic feet of airspace for each employee. For each occupant,
there shall be provided 4 square feet of free walking area and 3 square
feet of seating space, exclusive of area required for lavatory and
toilet facilities. The rated capacity shall be based on the stated
minimum space per employee and shall be posted at the chamber entrance.
The posted capacity shall not be exceeded, except in case of emergency.
(ii) Each special decompression chamber shall be equipped with the
following:
(A) A clock or clocks suitably placed so that the attendant and
the chamber occupants can readily ascertain the time;
(B) Pressure gauges which will indicate to the attendants and to
the chamber occupants the pressure in the chamber;
(C) Valves to enable the attendant to control the supply and discharge
of compressed air into and from the chamber.
(D) Valves and pipes, in connection with the air supply and exhaust,
arranged so that the chamber pressure can be controlled from within
and without;
(E) Effective means of oral intercommunication between the attendant,
occupants of the chamber, and the air compressor plant; and
(F) An observation port at the entrance to permit observation of
the chamber occupants.
(iii) Seating facilities in special decompression chambers shall
be so arranged as to permit a normal sitting posture without cramping.
Seating space, not less than 18 inches by 24 inches wide, shall be
provided per occupant.
(iv) Adequate toilet and washing facilities, in a screened or enclosed
recess, shall be provided. Toilet bowls shall have a built-in protector
on the rim so that an air space is created when the seat lid is closed.
(v) Fresh and pure drinking water shall be available. This may be
accomplished by either piping water into the special decompression
chamber and providing drinking fountains, or by providing individual
canteens, or by some other sanitary means. Community drinking vessels
are prohibited.
(vi) No refuse or discarded material of any kind shall be permitted
to accumulate, and the chamber shall be kept clean.
(vii) Unless the special decompression chamber is serving as the
man lock to atmospheric pressure, the special decompression chamber
shall be situated, where practicable, adjacent to the man lock on
the atmospheric pressure side of the bulkhead. A passageway shall
be provided, connecting the special chamber with the man lock, to
permit employees in the process of decompression to move from the
man lock to the special chamber without a reduction in the ambient
pressure from that designated for the next stage of decompression.
The passageway shall be so arranged as to not interfere with the normal
operation of the man lock, nor with the release of the occupants of
the special chamber to atmospheric pressure upon the completion of
the decompression procedure.
(8) Compressor plant and air supply.
(a) At all times there shall be a thoroughly experienced, competent,
and reliable person on duty at the air control valves as a gauge tender
who shall regulate the pressure in the working areas. During tunneling
operations, one gauge tender may regulate the pressure in not more than
two headings: Provided; That the gauges and controls are all in one
location. In caisson work, there shall be a gauge tender for each caisson.
(b) The low air compressor plant shall be of sufficient capacity to
not only permit the work to be done safely, but shall also provide a
margin to meet emergencies and repairs.
(c) Low air compressor units shall have at least two independent and
separate sources of power supply and each shall be capable of operating
the entire low air plant and its accessory systems.
(d) The capacity, arrangement, and number of compressors shall be sufficient
to maintain the necessary pressure without overloading the equipment
and to assure maintenance of such pressure in the working chamber during
periods of breakdown, repair, or emergency.
(e) Switching from one independent source of power supply to the other
shall be done periodically to ensure that workability of the apparatus
in an emergency.
(f) Duplicate low-pressure air feedlines and regulating valves shall
be provided between the source of air supply and a point beyond the
locks with one of the lines extending to within 100 feet of the working
face.
(g) All high-pressure and low-pressure air supply lines shall be equipped
with check valves.
(h) Low-pressure air shall be regulated automatically. In addition,
manually operated valves shall be provided for emergency conditions.
(i) The air intakes for all air compressors shall be located at a place
where fumes, exhaust gases, and other air contaminants will be at a
minimum.
(j) Gauges indicating the pressure in the working chamber shall be
installed in the compressor building, the lock attendant's station,
and at the employer's field office.
(9) Ventilation and air quality.
(a) Exhaust valves and exhaust pipes shall be provided and operated
so that the working chamber shall be well ventilated, and there shall
be no pockets of dead air. Outlets may be required at intermediate
points along the main low-pressure air supply line to the heading
to eliminate such pockets of dead air. The quantity of ventilation
air shall be not less than 30 cubic feet per minute.
(b) The air in the workplace shall be analyzed by the employer not
less than once each shift, and records of such tests shall be kept on
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