29 CFR Part 1910, Subpart T

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§ 1910.401

29 CFR Ch. XVII (7–1–07 Edition)

I, II, and III, Division 1, Hazardous (Classified)
Locations.
ASTM D3176–1989 (2002) Standard Practice
for Ultimate Analysis of Coal and Coke.
ASTM D3180–1989 (2002) Standard Practice
for Calculating Coal and Coke Analyses from
As-Determined to Different Bases.
NFPA 20–2003 Standard for the Installation
of Stationary Pumps for Fire Protection.
NFPA 30–2003 Flammable and Combustible
Liquids Code.
NFPA 32–2004 Standard for Drycleaning
Plants.
NFPA 33–2003 Standard for Spray Application Using Flammable or Combustible Materials.
NFPA 34–2003 Standard for Dipping and
Coating Processes Using Flammable or Combustible Liquids.
NFPA 35–2005 Standard for the Manufacture
of Organic Coatings.
NFPA 36–2004 Standard for Solvent Extraction Plants.
NFPA 40–2001 Standard for the Storage and
Handling of Cellulose Nitrate Film.
NFPA 58–2004 Liquefied Petroleum Gas Code.
NFPA 59–2004 Utility LP-Gas Plant Code.
NFPA 70–2002 National Electrical Code. (See
also NFPA 70–2005.)
NFPA 70E–2000 Standard for Electrical Safety
Requirements for Employee Workplaces. (See
also NFPA 70E–2004.)
NFPA 77–2000 Recommended Practice on Static Electricity.
NFPA 80–1999 Standard for Fire Doors and
Fire Windows.
NFPA 88A–2002 Standard for Parking Structures.
NFPA 91–2004 Standard for Exhaust Systems
for Air Conveying of Vapors, Gases, Mists, and
Noncombustible Particulate Solids.
NFPA 101–2006 Life Safety Code.
NFPA 496–2003 Standard for Purged and
Pressurized Enclosures for Electrical Equipment.
NFPA 497–2004 Recommended Practice for the
Classification of Flammable Liquids, Gases, or
Vapors and of Hazardous (Classified) Locations
for Electrical Installations in Chemical Process
Areas.
NFPA 505–2006 Fire Safety Standard for Powered Industrial Trucks Including Type Designations, Areas of Use, Conversions, Maintenance,
and Operation.
NFPA 820–2003 Standard for Fire Protection
in Wastewater Treatment and Collection Facilities.
NMAB 353–1–1979 Matrix of Combustion-Relevant Properties and Classification of Gases,
Vapors, and Selected Solids.
NMAB 353–2–1979 Test Equipment for Use in
Determining Classifications of Combustible
Dusts.
NMAB 353–3–1980 Classification of Combustible Dust in Accordance with the National
Electrical Code.

APPENDIX B TO SUBPART S OF PART
1910—EXPLANATORY DATA [RESERVED]
EFFECTIVE DATE NOTE: At 72 FR 7221, Feb.
14, 2007, Appendix B was removed, effective
Aug. 13, 2007.

APPENDIX C TO SUBPART S OF PART
1910—TABLES, NOTES, AND CHARTS
[RESERVED]
PUBLISHED AT 72 FR 7221, FEBRUARY
14, 2007.
EFFECTIVE DATE NOTE: At 72 FR 7221, Feb.
14, 2007, Appendix C was removed, effective
Aug. 13, 2007.

Subpart T—Commercial Diving
Operations
AUTHORITY: Sections 4, 6, and 8 of the Occupational Safety and Health Act of 1970 (29
U.S.C. 653, 655, and 657); Sec. 107, Contract
Work Hours and Safety Standards Act (the
Construction Safety Act) (40 U.S.C. 333); Sec.
41, Longshore and Harbor Workers’ Compensation Act (33 U.S.C. 941); Secretary of
Labor’s Order No. 8–76 (41 FR 25059), 9–83 (48
FR 35736), 1–90 (55 FR 9033), 3–2000 (65 FR
50017), or 5–2002 (67 FR 65008) as applicable; 29
CFR part 1911.
SOURCE: 42 FR 37668, July 22, 1977, unless
otherwise noted.

GENERAL
§ 1910.401

Scope and application.

(a) Scope. (1) This subpart (standard)
applies to every place of employment
within the waters of the United States,
or within any State, the District of Columbia, the Commonwealth of Puerto
Rico, the Virgin Islands, American
Samoa, Guam, the Trust Territory of
the Pacific Islands, Wake Island, Johnston Island, the Canal Zone, or within
the Outer Continental Shelf lands as
defined in the Outer Continental Shelf
Lands Act (67 Stat. 462, 43 U.S.C. 1331),
where diving and related support operations are performed.
(2) This standard applies to diving
and related support operations conducted in connection with all types of
work and employments, including general industry, construction, ship repairing, shipbuilding, shipbreaking and
longshoring. However, this standard
does not apply to any diving operation:

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Occupational Safety and Health Admin., Labor
(i) Performed solely for instructional
purposes, using open-circuit, compressed-air SCUBA and conducted
within the no-decompression limits;
(ii) Performed solely for search, rescue, or related public safety purposes
by or under the control of a governmental agency; or
(iii) Governed by 45 CFR part 46 (Protection of Human Subjects, U.S. Department of Health and Human Services) or equivalent rules or regulations
established by another federal agency,
which regulate research, development,
or related purposes involving human
subjects.
(iv) Defined as scientific diving and
which is under the direction and control of a diving program containing at
least the following elements:
(A) Diving safety manual which includes at a minimum: Procedures covering all diving operations specific to
the program; procedures for emergency
care, including recompression and
evacuation; and criteria for diver training and certification.
(B) Diving control (safety) board,
with the majority of its members being
active divers, which shall at a minimum have the authority to: Approve
and monitor diving projects; review
and revise the diving safety manual;
assure compliance with the manual;
certify the depths to which a diver has
been trained; take disciplinary action
for unsafe practices; and, assure adherence to the buddy system (a diver is accompanied by and is in continuous contact with another diver in the water)
for SCUBA diving.
(3) Alternative requirements for recreational diving instructors and diving
guides. Employers of recreational diving instructors and diving guides are
not required to comply with the decompression-chamber
requirements
specified by paragraphs (b)(2) and
(c)(3)(iii) of § 1910.423 and paragraph
(b)(1) of § 1910.426 when they meet all of
the following conditions:
(i) The instructor or guide is engaging solely in recreational diving instruction or dive-guiding operations;
(ii) The instructor or guide is diving
within the no-decompression limits in
these operations;
(iii) The instructor or guide is using
a nitrox breathing-gas mixture con-

§ 1910.402

sisting of a high percentage of oxygen
(more than 22% by volume) mixed with
nitrogen;
(iv) The instructor or guide is using
an open-circuit, semi-closed-circuit, or
closed-circuit self-contained underwater breathing apparatus (SCUBA);
and
(v) The employer of the instructor or
guide is complying with all requirements of Appendix C of this subpart.
(b) Application in emergencies. An employer may deviate from the requirements of this standard to the extent
necessary to prevent or minimize a situation which is likely to cause death,
serious physical harm, or major environmental damage, provided that the
employer:
(1) Notifies the Area Director, Occupational Safety and Health Administration within 48 hours of the onset of
the emergency situation indicating the
nature of the emergency and extent of
the deviation from the prescribed regulations; and
(2) Upon request from the Area Director, submits such information in writing.
(c) Employer obligation. The employer
shall be responsible for compliance
with:
(1) All provisions of this standard of
general applicability; and
(2) All requirements pertaining to
specific diving modes to the extent diving operations in such modes are conducted.
[42 FR 37668, July 22, 1977, as amended at 47
FR 53365, Nov. 26, 1982; 58 FR 35310, June 30,
1993; 69 FR 7363, Feb. 17, 2004]

§ 1910.402

Definitions.

As used in this standard, the listed
terms are defined as follows:
Acfm: Actual cubic feet per minute.
ASME Code or equivalent: ASME
(American Society of Mechanical Engineers) Boiler and Pressure Vessel Code,
Section VIII, or an equivalent code
which the employer can demonstrate
to be equally effective.
ATA: Atmosphere absolute.
Bell: An enclosed compartment, pressurized (closed bell) or unpressurized
(open bell), which allows the diver to
be transported to and from the underwater work area and which may be

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§ 1910.402

29 CFR Ch. XVII (7–1–07 Edition)

used as a temporary refuge during diving operations.
Bottom time: The total elasped time
measured in minutes from the time
when the diver leaves the surface in descent to the time that the diver begins
ascent.
Bursting pressure: The pressure at
which a pressure containment device
would fail structurally.
Cylinder: A pressure vessel for the
storage of gases.
Decompression chamber: A pressure
vessel for human occupancy such as a
surface decompression chamber, closed
bell, or deep diving system used to decompress divers and to treat decompression sickness.
Decompression sickness: A condition
with a variety of symptoms which may
result from gas or bubbles in the tissues of divers after pressure reduction.
Decompression table: A profile or set of
profiles of depth-time relationships for
ascent rates and breathing mixtures to
be followed after a specific depth-time
exposure or exposures.
Dive-guiding operations means leading
groups of sports divers, who use an
open-circuit, semi-closed-circuit, or
closed-circuit self-contained underwater breathing apparatus, to local undersea diving locations for recreational
purposes.
Dive location: A surface or vessel from
which a diving operation is conducted.
Dive-location reserve breathing gas: A
supply system of air or mixed-gas (as
appropriate) at the dive location which
is independent of the primary supply
system and sufficient to support divers
during the planned decompression.
Dive team: Divers and support employees involved in a diving operation,
including the designated person-incharge.
Diver: An employee working in water
using underwater apparatus which supplies compressed breathing gas at the
ambient pressure.
Diver-carried reserve breathing gas: A
diver-carried supply of air or mixed gas
(as appropriate) sufficient under standard operating conditions to allow the
diver to reach the surface, or another
source of breathing gas, or to be
reached by a standby diver.
Diving mode: A type of diving requiring specific equipment, procedures and

techniques (SCUBA, surface-supplied
air, or mixed gas).
Fsw: Feet of seawater (or equivalent
static pressure head).
Heavy gear: Diver-worn deep-sea dress
including helmet, breastplate, dry suit,
and weighted shoes.
Hyperbaric conditions: Pressure conditions in excess of surface pressure.
Inwater stage: A suspended underwater platform which supports a diver
in the water.
Liveboating: The practice of supporting a surfaced-supplied air or
mixed gas diver from a vessel which is
underway.
Mixed-gas diving: A diving mode in
which the diver is supplied in the water
with a breathing gas other than air.
No-decompression limits: The depthtime limits of the ‘‘no-decompression
limits and repetitive dive group designation table for no-decompression air
dives’’, U.S. Navy Diving Manual or
equivalent limits which the employer
can demonstrate to be equally effective.
Psi(g): Pounds per square inch
(gauge).
Recreational diving instruction means
training diving students in the use of
recreational diving procedures and the
safe operation of diving equipment, including an open-circuit, semi-closedcircuit, or closed-circuit self-contained
underwater breathing apparatus, during dives.
Scientific diving means diving performed solely as a necessary part of a
scientific, research, or educational activity by employees whose sole purpose
for diving is to perform scientific research tasks. Scientific diving does not
include performing any tasks usually
associated with commercial diving
such as: Placing or removing heavy objects underwater; inspection of pipelines and similar objects; construction;
demolition; cutting or welding; or the
use of explosives.
SCUBA diving: A diving mode independent of surface supply in which the
diver uses open circuit self-contained
underwater breathing apparatus.
Standby diver: A diver at the dive location available to assist a diver in the
water.
Surface-supplied air diving: A diving
mode in which the diver in the water is

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[42 FR 37668, July 22, 1977, as amended at 47
FR 53365, Nov. 26, 1982; 69 FR 7363, Feb. 17,
2004]

(2) The employer shall not require a
dive team member to be exposed to
hyperbaric conditions against the employee’s will, except when necessary to
complete decompression or treatment
procedures.
(3) The employer shall not permit a
dive team member to dive or be otherwise exposed to hyperbaric conditions
for the duration of any temporary
physical impairment or condition
which is known to the employer and is
likely to affect adversely the safety or
health of a dive team member.
(c) Designated person-in-charge. (1)
The employer or an employee designated by the employer shall be at the
dive location in charge of all aspects of
the diving operation affecting the safety and health of dive team members.
(2) The designated person-in-charge
shall have experience and training in
the conduct of the assigned diving operation.

PERSONNEL REQUIREMENTS

GENERAL OPERATIONS PROCEDURES

§ 1910.410 Qualifications of dive team.
(a) General. (1) Each dive team member shall have the experience or training necessary to perform assigned
tasks in a safe and healthful manner.
(2) Each dive team member shall
have experience or training in the following:
(i) The use of tools, equipment and
systems relevant to assigned tasks;
(ii) Techniques of the assigned diving
mode: and
(iii) Diving operations and emergency procedures.
(3) All dive team members shall be
trained in cardiopulmonary resuscitation and first aid (American Red Cross
standard course or equivalent).
(4) Dive team members who are exposed to or control the exposure of others to hyperbaric conditions shall be
trained in diving-related physics and
physiology.
(b) Assignments. (1) Each dive team
member shall be assigned tasks in accordance with the employee’s experience or training, except that limited
additional tasks may be assigned to an
employee undergoing training provided
that these tasks are performed under
the direct supervision of an experienced dive team member.

§ 1910.420 Safe practices manual.
(a) General. The employer shall develop and maintain a safe practices
manual which shall be made available
at the dive location to each dive team
member.
(b) Contents. (1) The safe practices
manual shall contain a copy of this
standard and the employer’s policies
for implementing the requirements of
this standard.
(2) For each diving mode engaged in,
the safe practices manual shall include:
(i) Safety procedures and checklists
for diving operations;
(ii) Assignments and responsibilities
of the dive team members;
(iii)
Equipment
procedures
and
checklists; and
(iv) Emergency procedures for fire,
equipment failure, adverse environmental conditions, and medical illness
and injury.

supplied from the dive location with
compressed air for breathing.
Treatment table: A depth-time and
breathing gas profile designed to treat
decompression sickness.
Umbilical: The composite hose bundle
between a dive location and a diver or
bell, or between a diver and a bell,
which supplies the diver or bell with
breathing gas, communications, power,
or heat as appropriate to the diving
mode or conditions, and includes a
safety line between the diver and the
dive location.
Volume tank: A pressure vessel connected to the outlet of a compressor
and used as an air reservoir.
Working pressure: The maximum pressure to which a pressure containment
device may be exposed under standard
operating conditions.

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§ 1910.421

[42 FR 37668, July 22, 1977, as amended at 49
FR 18295, Apr. 30, 1984]

§ 1910.421 Pre-dive procedures.
(a) General. The employer shall comply with the following requirements
prior to each diving operation, unless
otherwise specified.

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§ 1910.422

29 CFR Ch. XVII (7–1–07 Edition)

(b) Emergency aid. A list shall be kept
at the dive location of the telephone or
call numbers of the following:
(1) An operational decompression
chamber (if not at the dive location);
(2) Accessible hospitals;
(3) Available physicians;
(4) Available means of transportation; and
(5) The nearest U.S. Coast Guard Rescue Coordination Center.
(c) First aid supplies. (1) A first aid kit
appropriate for the diving operation
and approved by a physician shall be
available at the dive location.
(2) When used in a decompression
chamber or bell, the first aid kit shall
be suitable for use under hyperbaric
conditions.
(3) In addition to any other first aid
supplies, an American Red Cross standard first aid handbook or equivalent,
and a bag-type manual resuscitator
with transparent mask and tubing
shall be available at the dive location.
(d) Planning and assessment. Planning
of a diving operation shall include an
assessment of the safety and health aspects of the following:
(1) Diving mode;
(2) Surface and underwater conditions and hazards;
(3) Breathing gas supply (including
reserves);
(4) Thermal protection;
(5) Diving equipment and systems;
(6) Dive team assignments and physical fitness of dive team members (including any impairment known to the
employer);
(7) Repetitive dive designation or residual inert gas status of dive team
members;
(8) Decompression and treatment procedures (including altitude corrections); and
(9) Emergency procedures.
(e) Hazardous activities. To minimize
hazards to the dive team, diving operations shall be coordinated with other
activities in the vicinity which are
likely to interfere with the diving operation.
(f) Employee briefing. (1) Dive team
members shall be briefed on:
(i) The tasks to be undertaken;
(ii) Safety procedures for the diving
mode;

(iii) Any unusual hazards or environmental conditions likely to affect the
safety of the diving operation; and
(iv) Any modifications to operating
procedures necessitated by the specific
diving operation.
(2) Prior to making individual dive
team member assignments, the employer shall inquire into the dive team
member’s current state of physical fitness, and indicate to the dive team
member the procedure for reporting
physical problems or adverse physiological effects during and after the
dive.
(g) Equipment inspection. The breathing gas supply system including reserve breathing gas supplies, masks,
helmets, thermal protection, and bell
handling mechanism (when appropriate) shall be inspected prior to each
dive.
(h) Warning signal. When diving from
surfaces other than vessels in areas capable of supporting marine traffic, a
rigid replica of the international code
flag ‘‘A’’ at least one meter in height
shall be displayed at the dive location
in a manner which allows all-round visibility, and shall be illuminated during
night diving operations.
[42 FR 37668, July 22, 1977, as amended at 47
FR 14706, Apr. 6, 1982; 54 FR 24334, June 7,
1989]

§ 1910.422

Procedures during dive.

(a) General. The employer shall comply with the following requirements
which are applicable to each diving operation unless otherwise specified.
(b) Water entry and exit. (1) A means
capable of supporting the diver shall be
provided for entering and exiting the
water.
(2) The means provided for exiting
the water shall extend below the water
surface.
(3) A means shall be provided to assist an injured diver from the water or
into a bell.
(c) Communications. (1) An operational two-way voice communication
system shall be used between:
(i) Each surface-supplied air or
mixed-gas diver and a dive team member at the dive location or bell (when
provided or required); and
(ii) The bell and the dive location.

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Occupational Safety and Health Admin., Labor
(2) An operational, two-way communication system shall be available at
the dive location to obtain emergency
assistance.
(d) Decompression tables. Decompression, repetitive, and no-decompression
tables (as appropriate) shall be at the
dive location.
(e) Dive profiles. A depth-time profile,
including when appropriate any breathing gas changes, shall be maintained
for each diver during the dive including
decompression.
(f) Hand-held power tools and equipment. (1) Hand-held electrical tools and
equipment shall be de-energized before
being placed into or retrieved from the
water.
(2) Hand-held power tools shall not be
supplied with power from the dive location until requested by the diver.
(g) Welding and burning. (1) A current
supply switch to interrupt the current
flow to the welding or burning electrode shall be:
(i) Tended by a dive team member in
voice communication with the diver
performing the welding or burning; and
(ii) Kept in the open position except
when the diver is welding or burning.
(2) The welding machine frame shall
be grounded.
(3) Welding and burning cables, electrode holders, and connections shall be
capable of carrying the maximum current required by the work, and shall be
properly insulated.
(4) Insulated gloves shall be provided
to divers performing welding and burning operations.
(5) Prior to welding or burning on
closed compartments, structures or
pipes, which contain a flammable
vapor or in which a flammable vapor
may be generated by the work, they
shall be vented, flooded, or purged with
a mixture of gases which will not support combustion.
(h) Explosives. (1) Employers shall
transport, store, and use explosives in
accordance with this section and the
applicable provisions of § 1910.109 and
§ 1926.912 of Title 29 of the Code of Federal Regulations.
(2) Electrical continuity of explosive
circuits shall not be tested until the
diver is out of the water.
(3) Explosives shall not be detonated
while the diver is in the water.

§ 1910.423

(i) Termination of dive. The working
interval of a dive shall be terminated
when:
(1) A diver requests termination;
(2) A diver fails to respond correctly
to communications or signals from a
dive team member;
(3) Communications are lost and can
not be quickly re-established between
the diver and a dive team member at
the dive location, and between the designated person-in-charge and the person
controlling
the
vessel
in
liveboating operations; or
(4) A diver begins to use diver-carried
reserve breathing gas or the dive-location reserve breathing gas.
§ 1910.423

Post-dive procedures.

(a) General. The employer shall comply with the following requirements
which are applicable after each diving
operation, unless otherwise specified.
(b) Precautions. (1) After the completion of any dive, the employer shall:
(i) Check the physical condition of
the diver;
(ii) Instruct the diver to report any
physical problems or adverse physiological effects including symptoms of
decompression sickness;
(iii) Advise the diver of the location
of a decompression chamber which is
ready for use; and
(iv) Alert the diver to the potential
hazards of flying after diving.
(2) For any dive outside the no-decompression limits, deeper than 100 fsw
or using mixed gas as a breathing mixture, the employer shall instruct the
diver to remain awake and in the vicinity of the decompression chamber
which is at the dive location for at
least one hour after the dive (including
decompression or treatment as appropriate).
(c) Recompression capability. (1) A decompression chamber capable of recompressing the diver at the surface to
a minimum of 165 fsw (6 ATA) shall be
available at the dive location for:
(i) Surface-supplied air diving to
depths deeper than 100 fsw and
shallower than 220 fsw;
(ii) Mixed gas diving shallower than
300 fsw; or
(iii) Diving outside the no-decompression limits shallower than 300 fsw.

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§ 1910.424

29 CFR Ch. XVII (7–1–07 Edition)

(2) A decompression chamber capable
of recompressing the diver at the surface to the maximum depth of the dive
shall be available at the dive location
for dives deeper than 300 fsw.
(3) The decompression chamber shall
be:
(i) Dual-lock;
(ii) Multiplace; and
(iii) Located within 5 minutes of the
dive location.
(4) The decompression chamber shall
be equipped with:
(i) A pressure gauge for each pressurized compartment designed for human
occupancy;
(ii) A built-in-breathing-system with
a minimum of one mask per occupant;
(iii) A two-way voice communication
system between occupants and a dive
team member at the dive location;
(iv) A viewport; and
(v) Illumination capability to light
the interior.
(5) Treatment tables, treatment gas
appropriate to the diving mode, and
sufficient gas to conduct treatment
shall be available at the dive location.
(6) A dive team member shall be
available at the dive location during
and for at least one hour after the dive
to operate the decompression chamber
(when required or provided).
(d) Record of dive. (1) The following
information shall be recorded and
maintained for each diving operation:
(i) Names of dive team members including designated person-in-charge;
(ii) Date, time, and location;
(iii) Diving modes used;
(iv) General nature of work performed;
(v) Approximate underwater and surface conditions (visibility, water temperature and current); and
(vi) Maximum depth and bottom time
for each diver.
(2) For each dive outside the no-decompression limits, deeper than 100 fsw
or using mixed gas, the following additional information shall be recorded
and maintained:
(i) Depth-time and breathing gas profiles;
(ii) Decompression table designation
(including modification); and
(iii) Elapsed time since last pressure
exposure if less than 24 hours or repetitive dive designation for each diver.

(3) For each dive in which decompression sickness is suspected or symptoms
are evident, the following additional
information shall be recorded and
maintained:
(i) Description of decompression sickness symptoms (including depth and
time of onset); and
(ii) Description and results of treatment.
(e) Decompression procedure assessment. The employer shall:
(1) Investigate and evaluate each incident of decompression sickness based
on the recorded information, consideration of the past performance of decompression table used, and individual
susceptibility;
(2) Take appropriate corrective action to reduce the probability of recurrence of decompression sickness; and
(3) Prepare a written evaluation of
the decompression procedure assessment, including any corrective action
taken, within 45 days of the incident of
decompression sickness.
[42 FR 37668, July 22, 1977, as amended at 49
FR 18295, Apr. 30, 1984]

SPECIFIC OPERATIONS PROCEDURES
§ 1910.424

SCUBA diving.

(a) General. Employers engaged in
SCUBA diving shall comply with the
following requirements, unless otherwise specified.
(b) Limits. SCUBA diving shall not be
conducted:
(1) At depths deeper than 130 fsw;
(2) At depths deeper than 100 fsw or
outside the no-decompression limits
unless a decompression chamber is
ready for use;
(3) Against currents exceeding one (1)
knot unless line-tended; or
(4) In enclosed or physically confining spaces unless line-tended.
(c) Procedures. (1) A standby diver
shall be available while a diver is in
the water.
(2) A diver shall be line-tended from
the surface, or accompanied by another
diver in the water in continuous visual
contact during the diving operations.
(3) A diver shall be stationed at the
underwater point of entry when diving
is conducted in enclosed or physically
confining spaces.

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(4) A diver-carried reserve breathing
gas supply shall be provided for each
diver consisting of:
(i) A manual reserve (J valve); or
(ii) An independent reserve cylinder
with a separate regulator or connected
to the underwater breathing apparatus.
(5) The valve of the reserve breathing
gas supply shall be in the closed position prior to the dive.
§ 1910.425 Surface-supplied air diving.
(a) General. Employers engaged in
surface-supplied air diving shall comply with the following requirements,
unless otherwise specified.
(b) Limits. (1) Surface-supplied air
diving shall not be conducted at depths
deeper than 190 fsw, except that dives
with bottom times of 30 minutes or less
may be conducted to depths of 220 fsw.
(2) A decompression chamber shall be
ready for use at the dive location for
any dive outside the no-decompression
limits or deeper than 100 fsw.
(3) A bell shall be used for dives with
an inwater decompression time greater
than 120 minutes, except when heavy
gear is worn or diving is conducted in
physically confining spaces.
(c) Procedures. (1) Each diver shall be
continuously tended while in the
water.
(2) A diver shall be stationed at the
underwater point of entry when diving
is conducted in enclosed or physically
confining spaces.
(3) Each diving operation shall have a
primary breathing gas supply sufficient
to support divers for the duration of
the planned dive including decompression.
(4) For dives deeper than 100 fsw or
outside the no-decompression limits:
(i) A separate dive team member
shall tend each diver in the water;
(ii) A standby diver shall be available
while a diver is in the water;
(iii) A diver-carried reserve breathing
gas supply shall be provided for each
diver except when heavy gear is worn;
and
(iv) A dive-location reserve breathing
gas supply shall be provided.
(5) For heavy-gear diving deeper than
100 fsw or outside the no-decompression
limits:
(i) An extra breathing gas hose capable of supplying breathing gas to the

§ 1910.426

diver in the water shall be available to
the standby diver.
(ii) An inwater stage shall be provided to divers in the water.
(6) Except when heavy gear is worn
or where physical space does not permit, a diver-carried reserve breathing
gas supply shall be provided whenever
the diver is prevented by the configuration of the dive area from ascending directly to the surface.
§ 1910.426 Mixed-gas diving.
(a) General. Employers engaged in
mixed-gas diving shall comply with the
following requirements, unless otherwise specified.
(b) Limits. Mixed-gas diving shall be
conducted only when:
(1) A decompression chamber is ready
for use at the dive location; and
(i) A bell is used at depths greater
than 220 fsw or when the dive involves
inwater decompression time of greater
than 120 minutes, except when heavy
gear is worn or when diving in physically confining spaces; or
(ii) A closed bell is used at depths
greater than 300 fsw, except when diving is conducted in physically confining spaces.
(c) Procedures. (1) A separate dive
team member shall tend each diver in
the water.
(2) A standby diver shall be available
while a diver is in the water.
(3) A diver shall be stationed at the
underwater point of entry when diving
is conducted in enclosed or physically
confining spaces.
(4) Each diving operation shall have a
primary breathing gas supply sufficient
to support divers for the duration of
the planned dive including decompression.
(5) Each diving operation shall have a
dive-location reserve breathing gas
supply.
(6) When heavy gear is worn:
(i) An extra breathing gas hose capable of supplying breathing gas to the
diver in the water shall be available to
the standby diver; and
(ii) An inwater stage shall be provided to divers in the water.
(7) An inwater stage shall be provided
for divers without access to a bell for
dives deeper than 100 fsw or outside the
no-decompression limits.

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§ 1910.427

29 CFR Ch. XVII (7–1–07 Edition)

(8) When a closed bell is used, one
dive team member in the bell shall be
available and tend the diver in the
water.
(9) Except when heavy gear is worn
or where physical space does not permit, a diver-carried reserve breathing
gas supply shall be provided for each
diver:
(i) Diving deeper than 100 fsw or outside the no-decompression limits; or
(ii) Prevented by the configuration of
the dive area from directly ascending
to the surface.
§ 1910.427

Liveboating.

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(a) General. Employers engaged in
diving operations involving liveboating
shall comply with the following requirements.
(b) Limits. Diving operations involving liveboating shall not be conducted:
(1) With an inwater decompression
time of greater than 120 minutes;
(2) Using surface-supplied air at
depths deeper than 190 fsw, except that
dives with bottom times of 30 minutes
or less may be conducted to depths of
220 fsw;
(3) Using mixed gas at depths greater
than 220 fsw;
(4) In rough seas which significantly
inpede diver mobility or work function;
or
(5) In other than daylight hours.
(c) Procedures. (1) The propeller of the
vessel shall be stopped before the diver
enters or exits the water.
(2) A device shall be used which minimizes the possibility of entanglement
of the diver’s hose in the propeller of
the vessel.
(3) Two-way voice communication between the designated person-in-charge
and the person controlling the vessel
shall be available while the diver is in
the water.
(4) A standby diver shall be available
while a diver is in the water.
(5) A diver-carried reserve breathing
gas supply shall be carried by each
diver engaged in liveboating operations.

EQUIPMENT PROCEDURES AND
REQUIREMENTS
§ 1910.430

Equipment.

(a) General. (1) All employers shall
comply with the following requirements, unless otherwise specified.
(2) Each equipment modification, repair, test, calibration or maintenance
service shall be recorded by means of a
tagging or logging system, and include
the date and nature of work performed,
and the name or initials of the person
performing the work.
(b) Air compressor system. (1) Compressors used to supply air to the diver
shall be equipped with a volume tank
with a check valve on the inlet side, a
pressure gauge, a relief valve, and a
drain valve.
(2) Air compressor intakes shall be
located away from areas containing exhaust or other contaminants.
(3) Respirable air supplied to a diver
shall not contain:
(i) A level of carbon monoxide (CO)
greater than 20 p/m;
(ii) A level of carbon dioxide (CO2)
greater than 1,000 p/m;
(iii) A level of oil mist greater than 5
milligrams per cubic meter; or
(iv) A noxious or pronounced odor.
(4) The output of air compressor systems shall be tested for air purity
every 6 months by means of samples
taken at the connection to the distribution system, except that non-oil
lubricated compressors need not be
tested for oil mist.
(c) Breathing gas supply hoses. (1)
Breathing gas supply hoses shall:
(i) Have a working pressure at least
equal to the working pressure of the
total breathing gas system;
(ii) Have a rated bursting pressure at
least equal to 4 times the working pressure;
(iii) Be tested at least annually to 1.5
times their working pressure; and
(iv) Have their open ends taped,
capped or plugged when not in use.
(2) Breathing gas supply hose connectors shall:
(i) Be made of corrosion-resistant
materials;
(ii) Have a working pressure at least
equal to the working pressure of the
hose to which they are attached; and

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Occupational Safety and Health Admin., Labor
(iii) Be resistant to accidental disengagement.
(3) Umbilicals shall:
(i) Be marked in 10-ft. increments to
100 feet beginning at the diver’s end,
and in 50 ft. increments thereafter;
(ii) Be made of kink-resistant materials; and
(iii) Have a working pressure greater
than the pressure equivalent to the
maximum depth of the dive (relative to
the supply source) plus 100 psi.
(d) Buoyancy control. (1) Helmets or
masks connected directly to the dry
suit or other buoyancy-changing equipment shall be equipped with an exhaust
valve.
(2) A dry suit or other buoyancychanging equipment not directly connected to the helmet or mask shall be
equipped with an exhaust valve.
(3) When used for SCUBA diving, a
buoyancy compensator shall have an
inflation source separate from the
breathing gas supply.
(4) An inflatable flotation device capable of maintaining the diver at the
surface in a face-up position, having a
manually activated inflation source
independent of the breathing supply,
an oral inflation device, and an exhaust
valve shall be used for SCUBA diving.
(e) Compressed gas cylinders. Compressed gas cylinders shall:
(1) Be designed, constructed and
maintained in accordance with the applicable provisions of 29 CFR 1910.101
and 1910.169 through 1910.171.
(2) Be stored in a ventilated area and
protected from excessive heat;
(3) Be secured from falling; and
(4) Have shut-off valves recessed into
the cylinder or protected by a cap, except when in use or manifolded, or
when used for SCUBA diving.
(f) Decompression chambers. (1) Each
decompression chamber manufactured
after the effective date of this standard, shall be built and maintained in
accordance with the ASME Code or
equivalent.
(2) Each decompression chamber
manufactured prior to the effective
date of this standard shall be maintained in conformity with the code requirements to which it was built, or
equivalent.
(3) Each decompression chamber
shall be equipped with:

§ 1910.430

(i) Means to maintain the atmosphere below a level of 25 percent oxygen by volume;
(ii) Mufflers on intake and exhaust
lines, which shall be regularly inspected and maintained;
(iii) Suction guards on exhaust line
openings; and
(iv) A means for extinguishing fire,
and shall be maintained to minimize
sources of ignition and combustible
material.
(g) Gauges and timekeeping devices. (1)
Gauges indicating diver depth which
can be read at the dive location shall
be used for all dives except SCUBA.
(2) Each depth gauge shall be deadweight tested or calibrated against a
master reference gauge every 6 months,
and when there is a discrepancy greater than two percent (2 percent) of full
scale between any two equivalent
gauges.
(3) A cylinder pressure gauge capable
of being monitored by the diver during
the dive shall be worn by each SCUBA
diver.
(4) A timekeeping device shall be
available at each dive location.
(h) Masks and helmets. (1) Surfacesupplied air and mixed-gas masks and
helmets shall have:
(i) A non-return valve at the attachment point between helmet or mask
and hose which shall close readily and
positively; and
(ii) An exhaust valve.
(2) Surface-supplied air masks and
helmets shall have a minimum ventilation rate capability of 4.5 acfm at any
depth at which they are operated or
the capability of maintaining the diver’s inspired carbon dioxide partial
pressure below 0.02 ATA when the diver
is producing carbon dioxide at the rate
of 1.6 standard liters per minute.
(i) Oxygen safety. (1) Equipment used
with oxygen or mixtures containing
over forty percent (40%) by volume oxygen shall be designed for oxygen service.
(2) Components (except umbilicals)
exposed to oxygen or mixtures containing over forty percent (40%) by volume oxygen shall be cleaned of flammable materials before use.
(3) Oxygen systems over 125 psig and
compressed air systems over 500 psig
shall have slow-opening shut-off valves.

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§ 1910.440

29 CFR Ch. XVII (7–1–07 Edition)

(j) Weights and harnesses. (1) Except
when heavy gear is worn, divers shall
be equipped with a weight belt or assembly capable of quick release.
(2) Except when heavy gear is worn
or in SCUBA diving, each diver shall
wear a safety harness with:
(i) A positive buckling device;
(ii) An attachment point for the umbilical to prevent strain on the mask or
helmet; and
(iii) A lifting point to distribute the
pull force of the line over the diver’s
body.
[39 FR 23502, June 27, 1974, as amended at 49
FR 18295, Apr. 30, 1984; 51 FR 33033, Sept. 18,
1986]

rfrederick on PROD1PC67 with CFR

RECORDKEEPING
§ 1910.440 Recordkeeping
requirements.
(a)(1) [Reserved]
(2) The employer shall record the occurrence of any diving-related injury
or illness which requires any dive team
member to be hospitalized for 24 hours
or more, specifying the circumstances
of the incident and the extent of any
injuries or illnesses.
(b) Availability of records. (1) Upon the
request of the Assistant Secretary of
Labor for Occupational Safety and
Health, or the Director, National Institute for Occupational Safety and
Health, Department of Health and
Human Services of their designees, the
employer shall make available for inspection and copying any record or
document required by this standard.
(2) Records and documents required
by this standard shall be provided upon
request to employees, designated representatives, and the Assistant Secretary in accordance with 29 CFR
1910.1020 (a)–(e) and (g)–(i). Safe practices manuals (§ 1910.420), depth-time
profiles (§ 1910.422), recordings of dives
(§ 1910.423), decompression procedure assessment evaluations (§ 1910.423), and
records of hospitalizations (§ 1910.440)
shall be provided in the same manner
as employee exposure records or analyses using exposure or medical records.
Equipment inspections and testing
records which pertain to employees
(§ 1910.430) shall also be provided upon
request to employees and their designated representatives.

(3) Records and documents required
by this standard shall be retained by
the employer for the following period:
(i) Dive team member medical
records
(physician’s
reports)
(§ 1910.411)—5 years;
(ii)
Safe
practices
manual
(§ 1910.420)—current document only;
(iii) Depth-time profile (§ 1910.422)—
until completion of the recording of
dive, or until completion of decompression procedure assessment where there
has been an incident of decompression
sickness;
(iv) Recording of dive (§ 1910.423)—1
year, except 5 years where there has
been an incident of decompression
sickness;
(v) Decompression procedure assessment evaluations (§ 1910.423)—5 years;
(vi) Equipment inspections and testing records (§ 1910.430)—current entry
or tag, or until equipment is withdrawn from service;
(vii) Records of hospitalizations
(§ 1910.440)—5 years.
(4) After the expiration of the retention period of any record required to be
kept for five (5) years, the employer
shall forward such records to the National Institute for Occupational Safety and Health, Department of Health
and Human Services. The employer
shall also comply with any additional
requirements set forth at 29 CFR
1910.20(h).
(5) In the event the employer ceases
to do business:
(i) The successor employer shall receive and retain all dive and employee
medical records required by this standard; or
(ii) If there is no successor employer,
dive and employee medical records
shall be forwarded to the National Institute for Occupational Safety and
Health, Department of Health and
Human Services.
[42 FR 37668, July 22, 1977, as amended at 45
FR 35281, May 23, 1980; 47 FR 14706, Apr. 6,
1982; 51 FR 34562, Sept. 29, 1986; 61 FR 9242,
Mar. 7, 1996; 71 FR 16672, Apr. 3, 2006]

APPENDIX A TO SUBPART T TO PART
1910—EXAMPLES
OF
CONDITIONS
WHICH MAY RESTRICT OR LIMIT EXPOSURE TO HYPERBARIC CONDITIONS
The following disorders may restrict or
limit occupational exposure to hyperbaric

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Occupational Safety and Health Admin., Labor
conditions depending on severity, presence of
residual effects, response to therapy, number
of occurrences, diving mode, or degree and
duration of isolation.
History of seizure disorder other than
early febrile convulsions.
Malignancies (active) unless treated and
without recurrence for 5 yrs.
Chronic inability to equalize sinus and/or
middle ear pressure.
Cystic or cavitary disease of the lungs.
Impaired organ function caused by alcohol
or drug use.
Conditions requiring continuous medication for control (e.g., antihistamines,
steroids, barbiturates, moodaltering drugs,
or insulin).
Meniere’s disease.
Hemoglobinopathies.
Obstructive or restrictive lung disease.
Vestibular end organ destruction.
Pneumothorax.
Cardiac abnormalities (e.g., pathological
heart
block,
valvular
disease,
intraventricular conduction defects other
than isolated right bundle branch block, angina pectoris, arrhythmia, coronary artery
disease).
Juxta-articular osteonecrosis.

APPENDIX B TO SUBPART T TO PART
1910—GUIDELINES FOR SCIENTIFIC DIVING
This appendix contains guidelines that will
be used in conjunction with § 1910.401(a)(2)(iv)
to determine those scientific diving programs which are exempt from the requirements for commercial diving. The guidelines
are as follows:
1. The Diving Control Board consists of a
majority of active scientific divers and has
autonomous and absolute authority over the
scientific diving program’s operations.
2. The purpose of the project using scientific diving is the advancement of science;
therefore, information and data resulting
from the project are non-proprietary.
3. The tasks of a scientific diver are those
of an observer and data gatherer. Construction and trouble-shooting tasks traditionally
associated with commercial diving are not
included within scientific diving.
4. Scientific divers, based on the nature of
their activities, must use scientific expertise
in studying the underwater environment
and, therefore, are scientists or scientists in
training.

rfrederick on PROD1PC67 with CFR

[50 FR 1050, Jan. 9, 1985]

Pt. 1910, Subpt. T, App. C

APPENDIX C TO SUBPART T TO PART
1910—ALTERNATIVE
CONDITIONS
UNDER § 1910.401(A)(3) FOR RECREATIONAL DIVING INSTRUCTORS AND
DIVING GUIDES (MANDATORY)
Paragraph (a)(3) of § 1910.401 specifies that
an employer of recreational diving instructors and diving guides (hereafter, ‘‘divers’’ or
‘‘employees’’) who complies with all of the
conditions of this appendix need not provide
a decompression chamber for these divers as
required under §§ 1910.423(b)(2) or (c)(3) or
1910.426(b)(1).
1. EQUIPMENT REQUIREMENTS FOR
REBREATHERS
(a) The employer must ensure that each
employee operates the rebreather (i.e., semiclosed-circuit and closed-circuit self-contained underwater breathing apparatuses
(hereafter, ‘‘SCUBAs’’)) according to the rebreather manufacturer’s instructions.
(b) The employer must ensure that each rebreather has a counterlung that supplies a
sufficient volume of breathing gas to their
divers to sustain the divers’ respiration
rates, and contains a baffle system and/or
other moisture separating system that keeps
moisture from entering the scrubber.
(c) The employer must place a moisture
trap in the breathing loop of the rebreather,
and ensure that:
(i) The rebreather manufacturer approves
both the moisture trap and its location in
the breathing loop; and
(ii) Each employee uses the moisture trap
according to the rebreather manufacturer’s
instructions.
(d) The employer must ensure that each rebreather has a continuously functioning
moisture sensor, and that:
(i) The moisture sensor connects to a visual (e.g., digital, graphic, analog) or auditory
(e.g., voice, pure tone) alarm that is readily
detectable by the diver under the diving conditions in which the diver operates, and
warns the diver of moisture in the breathing
loop in sufficient time to terminate the dive
and return safely to the surface; and
(ii) Each diver uses the moisture sensor according to the rebreather manufacturer’s instructions.
(e) The employer must ensure that each rebreather contains a continuously functioning CO2 sensor in the breathing loop, and
that:
(i) The rebreather manufacturer approves
the location of the CO2 sensor in the breathing loop;
(ii) The CO2 sensor is integrated with an
alarm that operates in a visual (e.g., digital,
graphic, analog) or auditory (e.g., voice, pure
tone) mode that is readily detectable by each
diver under the diving conditions in which
the diver operates; and

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Pt. 1910, Subpt. T, App. C

29 CFR Ch. XVII (7–1–07 Edition)

(iii) The CO2 alarm remains continuously
activated when the inhaled CO2 level reaches
and exceeds 0.005 atmospheres absolute
(ATA).
(f) Before each day’s diving operations, and
more often when necessary, the employer
must calibrate the CO2 sensor according to
the sensor manufacturer’s instructions, and
ensure that:
(i) The equipment and procedures used to
perform this calibration are accurate to
within 10% of a CO2 concentration of 0.005
ATA or less;
(ii) The equipment and procedures maintain this accuracy as required by the sensor
manufacturer’s instructions; and
(iii) The calibration of the CO2 sensor is accurate to within 10% of a CO2 concentration
of 0.005 ATA or less.
(g) The employer must replace the CO2 sensor when it fails to meet the accuracy requirements specified in paragraph 1(f)(iii) of
this appendix, and ensure that the replacement CO2 sensor meets the accuracy requirements specified in paragraph 1(f)(iii) of this
appendix before placing the rebreather in operation.
(h) As an alternative to using a continuously functioning CO2 sensor, the employer
may use a schedule for replacing CO2-sorbent
material provided by the rebreather manufacturer. The employer may use such a
schedule only when the rebreather manufacturer has developed it according to the canister-testing protocol specified below in Condition 11, and must use the canister within
the temperature range for which the manufacturer conducted its scrubber canister
tests following that protocol. Variations
above or below the range are acceptable only
after the manufacturer adds that lower or
higher temperature to the protocol.
(i) When using CO2-sorbent replacement
schedules, the employer must ensure that
each rebreather uses a manufactured (i.e.,
commercially pre-packed), disposable scrubber cartridge containing a CO2-sorbent material that:
(i) Is approved by the rebreather manufacturer;
(ii) Removes CO2 from the diver’s exhaled
gas; and
(iii) Maintains the CO2 level in the breathable gas (i.e., the gas that a diver inhales directly from the regulator) below a partial
pressure of 0.01 ATA.
(j) As an alternative to manufactured, disposable scrubber cartridges, the employer
may fill CO2 scrubber cartridges manually
with CO2-sorbent material when:
(i) The rebreather manufacturer permits
manual filling of scrubber cartridges;
(ii) The employer fills the scrubber cartridges according to the rebreather manufacturer’s instructions;
(iii) The employer replaces the CO2-sorbent
material using a replacement schedule devel-

oped under paragraph 1(h) of this appendix;
and
(iv) The employer demonstrates that manual filling meets the requirements specified
in paragraph 1(i) of this appendix.
(k) The employer must ensure that each
rebreather has an information module that
provides:
(i) A visual (e.g., digital, graphic, analog)
or auditory (e.g., voice, pure tone) display
that effectively warns the diver of solenoid
failure (when the rebreather uses solenoids)
and other electrical weaknesses or failures
(e.g., low battery voltage);
(ii) For a semi-closed circuit rebreather, a
visual display for the partial pressure of CO2,
or deviations above and below a preset CO2
partial pressure of 0.005 ATA; and
(iii) For a closed-circuit rebreather, a visual display for: partial pressures of O2 and
CO2, or deviations above and below a preset
CO2 partial pressure of 0.005 ATA and a preset O2 partial pressure of 1.40 ATA or lower;
gas temperature in the breathing loop; and
water temperature.
(l) Before each day’s diving operations, and
more often when necessary, the employer
must ensure that the electrical power supply
and electrical and electronic circuits in each
rebreather are operating as required by the
rebreather manufacturer’s instructions.
2. SPECIAL REQUIREMENTS FOR CLOSEDCIRCUIT REBREATHERS
(a) The employer must ensure that each
closed-circuit rebreather uses supply-pressure sensors for the O2 and diluent (i.e., air or
nitrogen) gases and continuously functioning
sensors for detecting temperature in the inhalation side of the gas-loop and the ambient
water.
(b) The employer must ensure that:
(i) At least two O2 sensors are located in
the inhalation side of the breathing loop; and
(ii) The O2 sensors are: functioning continuously; temperature compensated; and approved by the rebreather manufacturer.
(c) Before each day’s diving operations, and
more often when necessary, the employer
must calibrate O2 sensors as required by the
sensor manufacturer’s instructions. In doing
so, the employer must:
(i) Ensure that the equipment and procedures used to perform the calibration are accurate to within 1% of the O2 fraction by volume;
(ii) Maintain this accuracy as required by
the manufacturer of the calibration equipment;
(iii) Ensure that the sensors are accurate
to within 1% of the O2 fraction by volume;
(iv) Replace O2 sensors when they fail to
meet the accuracy requirements specified in
paragraph 2(c)(iii) of this appendix; and
(v) Ensure that the replacement O2 sensors
meet the accuracy requirements specified in

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Occupational Safety and Health Admin., Labor
paragraph 2(c)(iii) of this appendix before
placing a rebreather in operation.
(d) The employer must ensure that each
closed-circuit rebreather has:
(i) A gas-controller package with electrically operated solenoid O2-supply valves;
(ii) A pressure-activated regulator with a
second-stage diluent-gas addition valve;
(iii) A manually operated gas-supply bypass valve to add O2 or diluent gas to the
breathing loop; and
(iv) Separate O2 and diluent-gas cylinders
to supply the breathing-gas mixture.

reational Diving: The DSAT Recreational
Dive Planner,’’ published in 1994 by Hamilton
Research Ltd. (known commonly as the ‘‘1994
DSAT No-Decompression Tables’’).
(b) An employer may permit a diver to use
a dive-decompression computer designed to
regulate decompression when the dive-decompression computer uses the no-decompression limits specified in paragraph 5(a) of
this appendix, and provides output that reliably represents those limits.

3. O2 CONCENTRATION IN THE BREATHING GAS

(a) The employer must ensure that:
(i) Properly trained personnel mix nitroxbreathing gases, and that nitrogen is the
only inert gas used in the breathing-gas mixture; and
(ii) When mixing nitrox-breathing gases,
they mix the appropriate breathing gas before delivering the mixture to the breathinggas cylinders, using the continuous-flow or
partial-pressure mixing techniques specified
in the 2001 NOAA Diving Manual, or using a
filter-membrane system.
(b) Before the start of each day’s diving operations, the employer must determine the
O2 fraction of the breathing-gas mixture
using an O2 analyzer. In doing so, the employer must:
(i) Ensure that the O2 analyzer is accurate
to within 1% of the O2 fraction by volume.
(ii) Maintain this accuracy as required by
the manufacturer of the analyzer.
(c) When the breathing gas is a commercially supplied nitrox breathing-gas mixture,
the employer must ensure that the O2 meets
the medical USP specifications (Type I,
Quality Verification Level A) or aviator’s
breathing-oxygen specifications (Type I,
Quality Verification Level E) of CGA G–4.3–
2000 (‘‘Commodity Specification for Oxygen’’). In addition, the commercial supplier
must:
(i) Determine the O2 fraction in the breathing-gas mixture using an analytic method
that is accurate to within 1% of the O2 fraction by volume;
(ii) Make this determination when the
mixture is in the charged tank and after disconnecting the charged tank from the charging apparatus;
(iii) Include documentation of the O2-analysis procedures and the O2 fraction when delivering the charged tanks to the employer.
(d) Before producing nitrox breathing-gas
mixtures using a compressor in which the
gas pressure in any system component exceeds 125 pounds per square inch (psi), the:
(i) Compressor manufacturer must provide
the employer with documentation that the
compressor is suitable for mixing high-pressure air with the highest O2 fraction used in
the nitrox breathing-gas mixture when operated according to the manufacturer’s operating and maintenance specifications;

The employer must ensure that the fraction of O2 in the nitrox breathing-gas mixture:
(a) Is greater than the fraction of O2 in
compressed air (i.e., exceeds 22% by volume);
(b) For open-circuit SCUBA, never exceeds
a maximum fraction of breathable O2 of 40%
by volume or a maximum O2 partial pressure
of 1.40 ATA, whichever exposes divers to less
O2; and
(c) For a rebreather, never exceeds a maximum O2 partial pressure of 1.40 ATA.
4. REGULATING O2 EXPOSURES AND DIVING
DEPTH
(a) Regarding O2 exposure, the employer
must:
(i) Ensure that the exposure of each diver
to partial pressures of O2 between 0.60 and
1.40 ATA does not exceed the 24-hour singleexposure time limits specified either by the
2001 National Oceanic and Atmospheric Administration Diving Manual (the ‘‘2001 NOAA
Diving Manual’’), or by the report entitled
‘‘Enriched Air Operations and Resource
Guide’’ published in 1995 by the Professional
Association of Diving Instructors (known
commonly as the ‘‘1995 DSAT Oxygen Exposure Table’’); and
(ii) Determine a diver’s O2-exposure duration using the diver’s maximum O2 exposure
(partial pressure of O2) during the dive and
the total dive time (i.e., from the time the
diver leaves the surface until the diver returns to the surface).
(b) Regardless of the diving equipment
used, the employer must ensure that no
diver exceeds a depth of 130 feet of sea water
(‘‘fsw’’) or a maximum O2 partial pressure of
1.40 ATA, whichever exposes the diver to less
O2.
5. USE OF NO-DECOMPRESSION LIMITS

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Pt. 1910, Subpt. T, App. C

(a) For diving conducted while using nitrox
breathing-gas mixtures, the employer must
ensure that each diver remains within the
no-decompression limits specified for single
and repetitive air diving and published in the
2001 NOAA Diving Manual or the report entitled ‘‘Development and Validation of NoStop Decompression Procedures for Rec-

6. MIXING AND ANALYZING THE BREATHING GAS

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Pt. 1910, Subpt. T, App. C

29 CFR Ch. XVII (7–1–07 Edition)

(ii) Employer must comply with paragraph
6(e) of this appendix, unless the compressor
is rated for O2 service and is oil-less or oilfree; and
(iii) Employer must ensure that the compressor meets the requirements specified in
paragraphs (i)(1) and (i)(2) of § 1910.430 whenever the highest O2 fraction used in the mixing process exceeds 40%.
(e) Before producing nitrox breathing-gas
mixtures using an oil-lubricated compressor
to mix high-pressure air with O2, and regardless of the gas pressure in any system component, the:
(i)
Employer
must
use
only
uncontaminated air (i.e., air containing no
hydrocarbon particulates) for the nitrox
breathing-gas mixture;
(ii) Compressor manufacturer must provide
the employer with documentation that the
compressor is suitable for mixing the highpressure air with the highest O2 fraction
used in the nitrox breathing-gas mixture
when operated according to the manufacturer’s operating and maintenance specifications;
(iii) Employer must filter the high-pressure air to produce O2-compatible air;
(iv) The filter-system manufacturer must
provide the employer with documentation
that the filter system used for this purpose
is suitable for producing O2-compatible air
when operated according to the manufacturer’s operating and maintenance specifications; and
(v) Employer must continuously monitor
the air downstream from the filter for hydrocarbon contamination.
(f) The employer must ensure that diving
equipment using nitrox breathing-gas mixtures or pure O2 under high pressure (i.e., exceeding 125 psi) conforms to the O2-service
requirements specified in paragraphs (i)(1)
and (i)(2) of § 1910.430.

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7. EMERGENCY EGRESS
(a) Regardless of the type of diving equipment used by a diver (i.e., open-circuit
SCUBA or rebreathers), the employer must
ensure that the equipment contains (or incorporates) an open-circuit emergencyegress system (a ‘‘bail-out’’ system) in which
the second stage of the regulator connects to
a separate supply of emergency breathing
gas, and the emergency breathing gas consists of air or the same nitrox breathing-gas
mixture used during the dive.
(b) As an alternative to the ‘‘bail-out’’ system specified in paragraph 7(a) of this appendix, the employer may use:
(i) For open-circuit SCUBA, an emergencyegress system as specified in § 1910.424(c)(4);
or
(ii) For a semi-closed-circuit and closedcircuit rebreather, a system configured so
that the second stage of the regulator con-

nects to a reserve supply of emergency
breathing gas.
(c) The employer must obtain from the rebreather manufacturer sufficient information to ensure that the bail-out system performs reliably and has sufficient capacity to
enable the diver to terminate the dive and
return safely to the surface.
8. TREATING DIVING-RELATED MEDICAL
EMERGENCIES
(a) Before each day’s diving operations, the
employer must:
(i) Verify that a hospital, qualified healthcare professionals, and the nearest Coast
Guard Coordination Center (or an equivalent
rescue service operated by a state, county, or
municipal agency) are available to treat diving-related medical emergencies;
(ii) Ensure that each dive site has a means
to alert these treatment resources in a timely manner when a diving-related medical
emergency occurs; and
(iii) Ensure that transportation to a suitable decompression chamber is readily available when no decompression chamber is at
the dive site, and that this transportation
can deliver the injured diver to the decompression chamber within four (4) hours travel
time from the dive site.
(b) The employer must ensure that portable O2 equipment is available at the dive
site to treat injured divers. In doing so, the
employer must ensure that:
(i) The equipment delivers medical-grade
O2 that meets the requirements for medical
USP oxygen (Type I, Quality Verification
Level A) of CGA G–4.3–2000 (‘‘Commodity
Specification for Oxygen’’);
(ii) The equipment delivers this O2 to a
transparent mask that covers the injured
diver’s nose and mouth; and
(iii) Sufficient O2 is available for administration to the injured diver from the time
the employer recognizes the symptoms of a
diving-related medical emergency until the
injured diver reaches a decompression chamber for treatment.
(c) Before each day’s diving operations, the
employer must:
(i) Ensure that at least two attendants, either employees or non-employees, qualified
in first-aid and administering O2 treatment,
are available at the dive site to treat divingrelated medical emergencies; and
(ii) Verify their qualifications for this
task.
9. DIVING LOGS AND NO-DECOMPRESSION
TABLES
(a) Before starting each day’s diving operations, the employer must:
(i) Designate an employee or a non-employee to make entries in a diving log; and
(ii) Verify that this designee understands
the diving and medical terminology, and

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Occupational Safety and Health Admin., Labor
proper procedures, for making correct entries in the diving log.
(b) The employer must:
(i) Ensure that the diving log conforms to
the requirements specified by paragraph (d)
(‘‘Record of dive’’) of § 1910.423; and
(ii) Maintain a record of the dive according
to § 1910.440 (‘‘Recordkeeping requirements’’).
(c) The employer must ensure that a hardcopy of the no-decompression tables used for
the dives (as specified in paragraph 6(a) of
this appendix) is readily available at the dive
site, whether or not the divers use dive-decompression computers.
10. DIVER TRAINING
The employer must ensure that each diver
receives training that enables the diver to
perform work safely and effectively while
using open-circuit SCUBAs or rebreathers
supplied with nitrox breathing-gas mixtures.
Accordingly, each diver must be able to demonstrate the ability to perform critical tasks
safely and effectively, including, but not
limited to: recognizing the effects of breathing excessive CO2 and O2; taking appropriate
action after detecting excessive levels of CO2
and O2; and properly evaluating, operating,
and maintaining their diving equipment
under the diving conditions they encounter.
11. TESTING PROTOCOL FOR DETERMINING THE
CO2 LIMITS OF REBREATHER CANISTERS
(a) The employer must ensure that the rebreather manufacturer has used the following procedures for determining that the

Pt. 1910, Subpt. T, App. C

CO2-sorbent material meets the specifications of the sorbent material’s manufacturer:
(i) The North Atlantic Treating Organization CO2 absorbent-activity test;
(ii) The RoTap shaker and nested-sieves
test;
(iii) The Navy Experimental Diving Unit
(‘‘NEDU’’)-derived Schlegel test; and
(iv) The NEDU MeshFit software.
(b) The employer must ensure that the rebreather manufacturer has applied the following canister-testing materials, methods,
procedures, and statistical analyses:
(i) Use of a nitrox breathing-gas mixture
that has an O2 fraction maintained at 0.28
(equivalent to 1.4 ATA of O2 at 130 fsw, the
maximum O2 concentration permitted at this
depth);
(ii) While operating the rebreather at a
maximum depth of 130 fsw, use of a breathing
machine to continuously ventilate the rebreather with breathing gas that is at 100%
humidity and warmed to a temperature of
98.6 degrees F (37 degrees C) in the heatinghumidification chamber;
(iii) Measurement of the O2 concentration
of the inhalation breathing gas delivered to
the mouthpiece;
(iv) Testing of the canisters using the
three ventilation rates listed in Table I
below (with the required breathing-machine
tidal volumes and frequencies, and CO2-injection rates, provided for each ventilation
rate):

TABLE I—CANISTER TESTING PARAMETERS

22.5 ................................................................................
40.0 ................................................................................
62.5 ................................................................................
1 ATPS

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2 STPD

Breathing machine
frequencies
(breaths per min.)

Breathing machine
tidal volumes (L)

Ventilation rates (Lpm, ATPS 1)

1.5
2.0
2.5

CO2 injection rates
(Lpm, STPD 2)

15
20
25

0.90
1.35
2.25

means ambient temperature and pressure, saturated with water.
means standard temperature and pressure, dry; the standard temperature is 32 degrees F (0 degrees C).

(v) When using a work rate (i.e., breathingmachine tidal volume and frequency) other
than the work rates listed in the table above,
addition of the appropriate combinations of
ventilation rates and CO2-injection rates;
(vi) Performance of the CO2 injection at a
constant (steady) and continuous rate during
each testing trial;
(vii) Determination of canister duration
using a minimum of four (4) water temperatures, including 40, 50, 70, and 90 degrees F
(4.4, 10.0, 21.1, and 32.2 degrees C, respectively);
(viii) Monitoring of the breathing-gas temperature at the rebreather mouthpiece (at
the ‘‘chrome T’’ connector), and ensuring
that this temperature conforms to the tem-

perature of a diver’s exhaled breath at the
water temperature and ventilation rate used
during the testing trial; 1
(ix) Implementation of at least eight (8)
testing trials for each combination of temperature and ventilation-CO2-injection rates
(for example, eight testing trials at 40 degrees F using a ventilation rate of 22.5 Lpm
at a CO2-injection rate of 0.90 Lpm);
1 NEDU can provide the manufacturer with
information on the temperature of a diver’s
exhaled breath at various water temperatures and ventilation rates, as well as techniques and procedures used to maintain
these temperatures during the testing trials.

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§§ 1910.901–1910.999

29 CFR Ch. XVII (7–1–07 Edition)

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(x) Allowing the water temperature to vary
no more than ± 2.0 degrees F (± 1.0 degree C)
between each of the eight testing trials, and
no more than ± 1.0 degree F (± 0.5 degree C)
within each testing trial;
(xi) Use of the average temperature for
each set of eight testing trials in the statistical analysis of the testing-trial results,
with the testing-trial results being the time
taken for the inhaled breathing gas to reach
0.005 ATA of CO2 (i.e., the canister-duration
results);
(xii) Analysis of the canister-duration results using the repeated-measures statistics
described in NEDU Report 2–99;

(xiii) Specification of the replacement
schedule for the CO2-sorbent materials in
terms of the lower prediction line (or limit)
of the 95% confidence interval; and
(xiv) Derivation of replacement schedules
only by interpolating among, but not by extrapolating beyond, the depth, water temperatures, and exercise levels used during
canister testing.
[69 FR 7363, Feb. 17, 2004]

Subparts U–Y [Reserved]
§§ 1910.901–1910.999

[Reserved]

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