SCUBA diving requirements

The maximum depth allowed for SCUBA diving under 1910.424(b)(1) is 130 feet of seawater (fsw). This is the absolute depth limit set by the rule—do not plan dives deeper than 1910.424(b)(1).

A decompression chamber must be ready for use when dives are deeper than 100 fsw or when dives will be conducted outside the no-decompression limits. The standard requires employers to have a chamber available in those situations per 1910.424(b)(2).

• "Ready for use" means the employer must have the chamber accessible and prepared so it can be used without undue delay when decompression or treatment is needed.

SCUBA dives are not allowed against currents exceeding one (1) knot unless the diver is line-tended. The rule disallows diving in stronger currents except when the diver is secured and tended from the surface per 1910.424(b)(3).

• If you will dive in currents near or above 1 knot, plan for line-tending procedures before entering the water.

SCUBA diving is prohibited in enclosed or physically confining spaces unless the diver is line-tended. The standard requires line-tending in those situations to manage the additional hazards of confined-space diving per 1910.424(b)(4).

Yes — a standby diver must be available any time a diver is in the water. The rule explicitly requires a standby diver to be present to assist in emergencies per 1910.424(c)(1).

• Employers should ensure the standby diver is ready and equipped to deploy immediately.

The standard requires each diver to be either line-tended from the surface or accompanied by another diver in the water who maintains continuous visual contact during diving operations. This requirement appears in 1910.424(c)(2).

• Practically, if you are not using a surface line-tender, you must ensure a buddy diver stays in continuous sight of the working diver for the duration of the activity.

When diving is conducted in enclosed or physically confining spaces, the standard requires a diver to be stationed at the underwater point of entry. This stationing is mandatory for such environments per 1910.424(c)(3).

• Combined with 1910.424(b)(4), confined-space diving also requires line-tending, so plan both measures together.

Each diver must carry a reserve breathing gas supply that is either a manual reserve (a J valve) or an independent reserve cylinder with a separate regulator or connected to the underwater breathing apparatus. The acceptable options are set out in 1910.424(c)(4), 1910.424(c)(4)(i) and 1910.424(c)(4)(ii).

• Choose the reserve type that fits your equipment and dive profile, and ensure divers are trained to operate whichever reserve is provided.

The valve of the reserve breathing gas supply must be in the closed position before the dive begins. The standard requires this step to prevent accidental depletion of the reserve during the dive per 1910.424(c)(5).

• For example, set and verify a J-valve or reserve cylinder valve is closed during pre-dive checks.

For dives deeper than 100 fsw or dives outside no-decompression limits, the employer must ensure a decompression chamber is ready for use. That readiness is required by 1910.424(b)(2).

• "Ready for use" means the chamber should be accessible and prepared so it can be used promptly for decompression or treatment without unnecessary delay.

Line-tending is explicitly required when diving against currents exceeding one knot and when diving in enclosed or physically confining spaces. Additionally, the standard allows line-tending as one of the two options for maintaining contact with the diver in normal operations (the other option is continuous visual contact by another diver). See 1910.424(b)(3), 1910.424(b)(4), and 1910.424(c)(2).

• Plan line-tending when operating in strong currents, confined spaces, or anytime surface control is needed instead of buddy visual contact.

The employer is responsible for providing a standby diver and ensuring each diver carries an acceptable reserve breathing gas supply, because the standard places these operational requirements on the employer. See the standby-diver requirement at 1910.424(c)(1) and reserve gas requirements at 1910.424(c)(4) and 1910.424(c)(5).

• Employers should document procedures and pre-dive checks to demonstrate compliance with these provisions.

Yes — confined or physically confining-space dives require line-tending per 1910.424(b)(4) and also require a diver to be stationed at the underwater point of entry per 1910.424(c)(3). Additionally, general contact requirements in 1910.424(c)(2) mean the diver must be tended or accompanied by another diver in continuous visual contact.

• In practice, plan for surface line-tending plus a properly positioned entry/diver attendant for confined-space dives.

Employers may provide either a manual reserve (J valve) or an independent reserve cylinder with a separate regulator (or one connected to the underwater breathing apparatus) as the diver-carried reserve breathing supply; the standard permits both options in 1910.424(c)(4)(i) and 1910.424(c)(4)(ii).

• Choose the method that matches your equipment configuration, dive duration, and training; ensure divers know how to access and operate the selected reserve.