The FlowState Way: Training Philosophy, Policies & Procedures

Depth and gas do not injure a diver by themselves. They injure a diver whose judgment, gas management, or physiology could no longer keep pace with what depth and gas were quietly demanding. The limits in this section exist to keep that margin from disappearing without a diver noticing - and they apply across every FlowState Divers training, regardless of curriculum, unless a training-specific standard imposes something stricter.

Oxygen Exposure

Working ppO₂ must never be planned to exceed 1.2 ATA during the active phase of a dive - navigating, working a task, managing a team, or doing anything other than a controlled, stationary hang. This is deliberately more conservative than the ceiling much of the industry still treats as standard. A working diver's oxygen consumption, exertion, and CO₂ production are all higher than a resting diver's, and oxygen toxicity risk rises with exertion in ways a static ppO₂ number doesn't fully capture. Planning to 1.2 rather than 1.4 during the working phase buys back exactly the margin that exertion quietly spends.

During decompression - where the diver is stationary, controlled, and at a fixed depth for a known duration - ppO₂ may be planned up to 1.4 ATA, but never higher. This distinction is not arbitrary. A diver hanging on a stop is not task-loaded, not manoeuvring, and easier to monitor for early symptoms than a diver actively working at the same partial pressure. The lower exertion state genuinely changes the risk profile; the limit reflects that rather than ignoring it.

Both figures are ceilings, not targets. A dive planned closer to these limits than necessary is a dive with less margin than the plan required.

Maximum Depth on Air

30 meters is the maximum depth for any dive conducted on air, across every training in our curriculum. Beyond this depth, narcosis accumulates to a point where judgment - the exact faculty every other standard in this document depends on - can no longer be trusted to assess its own impairment. A narced diver rarely perceives themselves as narced; that is the nature of the impairment, not an exception to it. Extending this limit through experience, comfort, or repeated exposure is not something we allow, because comfort with narcosis and resistance to narcosis are not the same thing, and only one of them is real.

Dives planned beyond 30 meters require a helium-based mix appropriate to the depth, governed by the Equivalent Narcotic Depth limit below.

Equivalent Narcotic Depth

END must not exceed 30 meters on any dive, calculated on the assumption that helium is the only non-narcotic component of the breathing gas. This limit exists independently of maximum depth on air - a diver breathing trimix at 60 meters is still bound by the same narcotic ceiling as a diver breathing air at 30. Depth is not the variable that matters here. Narcotic load is, and it is managed through gas selection, not through willingness to tolerate its effects.

Decompression Limits

Training-specific standards define the maximum planned decompression obligation for each level of training, calculated using FlowState Divers' approved decompression methods. What is constant across every training is the principle underneath the number: decompression obligation is planned in advance, monitored throughout the dive, and never extended in real time to accommodate a dive that ran long, went deeper than planned, or simply felt like it could handle more. A plan that gets renegotiated underwater was never a plan. It was a guess with a number attached.

Reserve Gas

Every open-circuit dive is terminated as soon as any team member reaches their reserve gas. Reserve gas is the amount of gas required for two divers, sharing gas, to safely reach the surface - or another breathable gas supply - from the planned maximum depth of the dive. Every closed-circuit dive is terminated at bailout reserve gas, calculated on the same principle applied to an open-circuit bailout scenario. Reserve gas is not a number checked occasionally. It is tracked continuously, by every diver, for their own supply and their teammates', because the moment it's reached, the dive is over - regardless of how the plan felt five minutes earlier.

None of these figures are negotiable by comfort, experience, or how a particular dive happens to be going. They exist because narcosis, oxygen toxicity, and decompression obligation share the same dangerous property: the diver most affected by them is frequently the diver least equipped to notice it happening. The limit is the thing standing in for the judgment that impairment has already begun to erode. Every mentor at FlowState Divers holds their divers to these limits without exception, because the standard only protects anyone if it protects everyone, every time.