Diving equipment requirements

You must record every equipment modification, repair, test, calibration, or maintenance action with a tagging or logging system that shows the date, the nature of the work, and the name or initials of the person who performed it. See 1910.430(a)(2).

• Use a durable log or tag on the equipment (paper or electronic) that stays with the item or its storage location.
• Include the date of the work, a short description (e.g., "compressor safety valve replaced"), and the technician’s name or initials.
• Keep records long enough to demonstrate that periodic tests and required inspections (for example, annual hose tests) were performed.

An air compressor supplying a diver must have a volume tank with a check valve on the inlet side, a pressure gauge, a relief valve, and a drain valve. See 1910.430(b)(1).

• The volume tank smooths delivery and reduces pulsation.
• The inlet check valve prevents backflow into the compressor.
• The relief valve and pressure gauge protect against overpressure and allow safe monitoring.
• The drain valve allows removal of accumulated moisture.

Compressor intakes must be located away from areas containing exhaust or other contaminants so intake air is not polluted. See 1910.430(b)(2).

• Place intakes upwind and well clear of engine exhausts, vehicle parking, ventilation outlets, chemical storage, and other contaminant sources.
• Avoid enclosed spaces where fumes or vapors can collect.
• If clean air sources are limited, consider using intake filtration or relocating compressors.

Respirable air supplied to a diver must not contain more than 20 ppm carbon monoxide, more than 1,000 ppm carbon dioxide, an oil mist concentration greater than 5 mg/m³, or any noxious or pronounced odor. See 1910.430(b)(3).

• Monitor and test compressor output to ensure these limits are met.
• If odor is present, stop use until the source is identified and corrected.

The output of air compressor systems must be tested for air purity every six months using samples taken at the connection to the distribution system; however, non-oil-lubricated compressors are exempt from testing for oil mist. See 1910.430(b)(4).

• Take samples at the point where air enters the breathing distribution to reflect what divers receive.
• Keep test records in the equipment maintenance log required by 1910.430(a)(2).
• If a test fails, remove the air source from service until corrected and retested.

Breathing gas supply hoses must have a working pressure at least equal to the system working pressure, a rated bursting pressure at least four times the working pressure, and must be pressure-tested at least annually to 1.5 times their working pressure. See 1910.430(c)(1)(i)–(iii).

• Mark and record the hose working pressure and test date in your maintenance log per 1910.430(a)(2).
• After annual testing, tag hoses with test date and next due date.
• Take hoses out of service if they fail the pressure test or show damage.

When not in use, the open ends of breathing gas supply hoses must be taped, capped, or plugged. See 1910.430(c)(1)(iv).

• This prevents contamination (water, dirt, oil) from entering the hose and affecting air quality.
• Use caps/plugs compatible with the hose material and tag hoses indicating they are out of service if necessary.

Breathing gas hose connectors must be made of corrosion-resistant materials, have a working pressure at least equal to the working pressure of the hose they attach to, and be resistant to accidental disengagement. See 1910.430(c)(2)(i)–(iii).

• Use stainless steel or suitably coated fittings in marine environments to avoid corrosion.
• Match connector pressure ratings to hose ratings and the system maximum working pressure.
• Use mechanical locking or threaded connectors to prevent accidental disconnection during a dive.

Umbilicals must be marked in 10-foot increments to 100 feet beginning at the diver's end and in 50-foot increments thereafter, be made of kink-resistant materials, and have a working pressure greater than the pressure equivalent to the maximum dive depth (relative to the supply source) plus 100 psi. See 1910.430(c)(3)(i)–(iii).

• Marking helps attendants estimate depth and manage slack.
• Calculate required working pressure by converting maximum depth to psi and adding 100 psi as required.

Helmets or masks connected directly to the dry suit or other buoyancy-changing equipment must have an exhaust valve; dry suits or other buoyancy-changing equipment not directly connected to the helmet or mask must also have an exhaust valve; and when used for SCUBA diving, a buoyancy compensator must have an inflation source separate from the breathing gas supply. See 1910.430(d)(1)–(3).

• Exhaust valves allow controlled venting of excess buoyancy gas.
• SCUBA buoyancy inflation must not rely solely on breathing gas—use an independent inflation cylinder or manual device.
• For SCUBA, also provide an oral inflation device as required elsewhere in the standard.

For SCUBA diving, an inflatable flotation device must be capable of keeping the diver face-up at the surface, have a manually activated inflation source independent of the breathing supply, include an oral inflation device, and have an exhaust valve. See 1910.430(d)(4).

• The independent manual inflation source ensures positive buoyancy even if breathing gas fails.
• Oral inflation gives a backup if the manual inflator malfunctions.
• The exhaust valve prevents over-inflation and allows controlled descent.

Compressed gas cylinders used in diving operations must be designed, constructed, and maintained according to 29 CFR 1910.101 and 1910.169–1910.171; stored in a ventilated area and protected from excessive heat; secured to prevent falling; and have shut-off valves recessed or protected by a cap except when in use, manifolded, or used for SCUBA diving. See 1910.430(e)(1)–(4).

• Follow the referenced compressed gas cylinder rules at 1910.101 and 1910.169–1910.171.
• Secure cylinders with straps or chains to a fixed structure or approved rack so they cannot tip over.
• Keep cylinders away from heat sources and in well-ventilated storage.

Decompression chambers manufactured after the standard’s effective date must be built and maintained in accordance with the ASME Code or equivalent; chambers manufactured prior to the effective date must be maintained in conformity with the code requirements to which they were originally built or equivalent. See 1910.430(f)(1)–(2).

• For new chambers, follow the current ASME Boiler and Pressure Vessel Code requirements applicable to hyperbaric chambers.
• For older chambers, maintain them to the original applicable code level or an equivalent safety standard and document maintenance records.

Each decompression chamber must have means to keep the chamber atmosphere below 25 percent oxygen by volume, mufflers on intake and exhaust lines that are regularly inspected and maintained, suction guards on exhaust openings, and a means for extinguishing fire with minimization of ignition sources and combustible material. See 1910.430(f)(3)(i)–(iv).

• Atmosphere control reduces fire risk from elevated oxygen concentrations.
• Inspect mufflers and suction guards as part of routine chamber maintenance and keep records.
• Keep fire extinguishers or appropriate suppression nearby and remove unnecessary combustibles.

Depth gauges used for dives (except SCUBA) must be deadweight tested or calibrated against a master reference gauge every six months, and additionally whenever there is a discrepancy greater than two percent of full scale between equivalent gauges. See 1910.430(g)(2).

• Keep calibration records in your maintenance log per 1910.430(a)(2).
• Remove or repair any gauge that fails calibration before further use.

For SCUBA divers, each diver must wear a cylinder pressure gauge capable of being monitored during the dive; for all non-SCUBA dives, gauges indicating diver depth readable at the dive location must be used. A timekeeping device must also be available at each dive location. See 1910.430(g)(1)–(4).

• Ensure cylinder pressure gauges are accurate and visible to the diver throughout the dive.
• Keep a timekeeper at the dive site to manage bottom time and decompression schedules.

Surface-supplied air and mixed-gas masks and helmets must have a non-return (check) valve at the attachment point between the helmet or mask and hose that closes readily and positively, and they must have an exhaust valve. See 1910.430(h)(1)(i)–(ii).

• The non-return valve prevents backflow of contaminated water or gas into the supply hose.
• The exhaust valve allows the diver’s exhaled gas to leave the helmet without letting contaminants in.

Surface-supplied air masks and helmets must provide a minimum ventilation capability of 4.5 actual cubic feet per minute (acfm) at any operating depth, or be able to keep the diver’s inspired carbon dioxide partial pressure below 0.02 ATA when the diver produces CO2 at 1.6 standard liters per minute. See 1910.430(h)(2).

• Meeting either criterion ensures adequate removal of exhaled CO2 and prevents CO2 buildup that can cause narcosis or distress.
• Test ventilation performance at the working depth and document results in the equipment records.

Equipment used with oxygen or mixtures containing more than 40% oxygen by volume must be designed for oxygen service; components (except umbilicals) exposed to such oxygen-rich mixtures must be cleaned of flammable materials before use; and oxygen systems over 125 psig and compressed air systems over 500 psig must have slow-opening shut-off valves. See 1910.430(i)(1)–(3).

• Use oxygen-compatible materials and seals to avoid ignition hazards.
• Clean and handle oxygen system components using oxygen-clean procedures and document the cleaning.
• Use slow-opening valves at the pressure thresholds specified to prevent adiabatic compression heating and pressure shocks.

Except when heavy gear is worn, divers must have a weight belt or assembly capable of quick release; except when heavy gear is worn or for SCUBA diving, each diver must wear a safety harness with a positive buckling device, an attachment point for the umbilical to prevent strain on the mask or helmet, and a lifting point to distribute pull force over the diver’s body. See 1910.430(j)(1)–(2)(iii).

• Test quick-release mechanisms routinely so they function under load.
• Ensure harnesses have a certified lifting point that spreads force across the body to avoid injury during recovery.

Umbilicals must be marked in 10-foot increments up to 100 feet starting at the diver’s end, and in 50-foot increments beyond 100 feet. See 1910.430(c)(3)(i).

• Use permanent, high-contrast markings at the specified intervals so attendants can estimate depth and manage line slack safely.