I think the 12-hour surface interval rule is way too strict for most jobs

I've been diving commercial for about 8 years now, mostly doing inland bridge inspections around the Great Lakes. Everybody I know swears by the 12-hour surface interval before flying after a dive, but I think it's overkill unless you're doing deep saturation stuff. Last month I had a job near Cleveland where I was only at 30 feet for 45 minutes total. I had to fly home that same evening for a family thing, so I took a 4-hour surface interval instead. Felt fine, no hits or anything. My dive supervisor told me I was being an idiot, but the math on the Navy tables doesn't support waiting that long for shallow work. Has anyone else gone against the standard rules and been fine on a regular inland job?

2 comments

2 Comments

mason_ward1mo ago

Honestly, did you even hit your no decompression limit on that dive?

emma5221mo ago

You remember the Navy tables from your training too, right? The no decompression limits for 30 feet are basically infinite, you could stay down for like 8 hours and still be fine by the numbers. I've done the same thing plenty of times on bridge jobs in the Detroit River, shallow dives maybe 25 feet for an hour tops, then hopped on a plane three hours later. The risk is practically zero for that kind of work, it's not like we're doing 100 foot dives with long bottom times. Your supervisor is just covering himself because the company policy says 12 hours no matter what, but the actual science doesn't back it up for shallow stuff. I figure if I'm not even close to the no decompression limit, a few hours on the surface is plenty for my body to offgas.

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