What are the depths scuba divers can dive without needing to worry about decompression stops?
In my opinion many scuba divers get confused between ‘decompression’ and ‘decompression stops.’ This leads to a number of beginner scuba divers asking ‘how deep can you dive without decompression.’
Many beginner scuba divers ask 'how deep can you dive without decompression.' As all dives are decompression dives, the answer is: You can't dive without needing to decompress. A better question to ask is 'how deep can you dive without decompression stops?' Decompression stops are affected by how deep you dive and also by how much time you spend at your chosen depth. The deeper and longer your dive, the more chance you need decompression stops. For shallow dives between 6-10 metres (20-30 feet) you could spend many hours without needing to stop for decompression. But if you dive deeper than 30 metres (100 feet), your time at this depth is limited to around 20 minutes before a decompression stop is required.
What is decompression?
Firstly, let's look at what decompression is with regards to scuba diving.
If we look at the definition of decompression this states that: "Decompression is to release from pressure or compression" or "to undergo release from pressure."
When you scuba dive you enter an environment which is at higher pressure than it is on land. In fact water is nearly 800 times (784 times) more dense than air at sea level.
The deeper you go, the higher the pressure. The higher the pressure the more your body will be compressed. So by definition, as you ascend from ANY dive your body will be decompressing. That means that all dives are decompression dives.
When your body is under pressure the nitrogen element of the air you breath is dissolved into your body. The longer you are at depth, the more nitrogen that is dissolved. The more nitrogen that's been dissolved, the more time that is required for it to release from your body as you ascend and decompress.
How do scuba divers decompress?
The way that divers decompress is by ascending slowly. The gases (in particular nitrogen) that have dissolved into your bodily tissues under pressure at depth are released as you ascend, as the water pressure reduces.
If you were to ascend too quickly, these gasses (i.e. nitrogen) would escape too quickly and form bubbles. It's these nitrogen bubbles that are the problem.
It's these nitrogen bubbles that cause decompression sickness (DCS).
DCS or the bends can be potential fatal. This should therefore be avoided at all costs. This is why all scuba diving schools, navy training and other scuba diving experts advise you ascend at a slow rate.
Your ascent rate can either be controlled by using a dive computer. Or alternatively, you can ascend at a rate that's slower than the smallest of your exhaust bubbles from breathing.
More Reading: 12 decompression sickness risk factors
What is a decompression stop?
As a part of your ascent from depth, if the amount of nitrogen dissolved into your body exceeds a certain level, you may need to stop at certain intervals during your ascent. These stops allow additional time for the dissolved gases to escape slowly. Before you continue with your ascent to the surface.
This stop during your ascent is called a decompression stop.
A decompression stop is similar to a safety stop, except that a decompression stop is mandatory. Whereas a safety stop is precautionary. Both serve similar purposes, but if you miss a decompression stop, you risk getting decompression sickness. But if you miss a safety stop, you are less likely to run into problems.
However, it's worth taking note of the decompression sickness risk factors. As there are certain risk factors that could impact on your decompression time and on a safety stop becoming even more important.
More Reading: How do you do a decompression stop vs a safety stop?
How deep can you dive without decompression?
As already explained, all dives are decompression dives. I'm therefore going to explain about 'how deep and how long can you dive without a decompression stop,' instead of about 'how deep can you dive without decompression or without needing to decompress?'
The depth to which you dive and how long you stay at that depth will impact your decompression time. So it's not necessarily just about the depth you dive to on its own.
It's about a combination of the two variables that make the difference. That is;
- The depth of your dive, and;
- How long you dive for or 'your bottom time'.
For example, you could probably spend many hours at a depth of between 6-10 metres (20-30 feet), without having to worry about a decompression stop.
Your air is more likely to run out way before a decompression stop would become necessary. But you still need to ascend slowly from this depth, as you must from a deeper dive.
As you begin to dive deeper, the time you spend at these deeper depths will impact on the time you can spend on the bottom, before needing a decompression stop.
Below are a few examples of the amount of time you can spend at certain depths before requiring a decompression stop.
You'll notice how much your time is restricted at depths of more than 20-25 metres (66-82 feet).
Here's an example of the no decompression stop limits at various depths using the BSAC dive tables (Using Table A):
The following depths and no stop decompression times are based on the first dive of the day. That is, they assume you've not done any other dives beforehand.
- 9 metres (30 feet) dive depth: No decompression time limit of 243 minutes (PADI Tables 219 minutes at 10 metres (33 feet)).
- 15 metres (50 feet) dive depth: No decompression time limit of 74 minutes (PADI Tables 72 minutes).
- 18 metres (60 feet) dive depth: No decompression time limit of 51 minutes (PADI Tables 56 minutes).
- 24 metres (80 feet) dive depth: No decompression time limit of 30 minutes (PADI Tables 29 minutes).
- 30 metres (100 feet) dive depth: No decompression time limit of 20 minutes (PADI Tables 20 minutes).
- 33 metres (110 feet) dive depth: No decompression time limit of 17 minutes (PADI Tables 14 minutes).
- 40 metres (130 feet) dive depth: No decompression time limit of 12 minutes (PADI Tables 9 minutes).
- 50 metres (164 feet) dive depth: No decompression time limit of 8 minutes (PADI Tables NA as exceeds recreation dive depth limit).
If you go over any of these dive time limits at the depths shown, you will take yourself into decompression stop time.
More Reading: What are the common depths for experience scuba divers?
Once you enter decompression stop time diving, you'll need to take into account your air consumption during the time you need to decompress whilst stopped. As whilst you are stopped decompressing, you are using up air.
That means you need to consider how much air you'll consume during your decompression stops, in addition to the air you'll use up during the rest of your ascent. Always remembering to return to the surface with your reserve air.
More Reading: How deep can you dive with Nitrox?
How deep can you dive without a safety stop?
As already explained, a safety stop is a precautionary stop on your ascent from a dive. If for example, your dive is to a shallow depth of between 6-10 metres (20-30 feet), you wouldn't need to do a safety stop.
However, once you go deeper than 10-15+ metres (30-50+ feet), then I'd always recommend you carry out a 5-6 metres (16-20 feet) safety stop for three minutes for every dive you do.
Most dive organisations recommend this. Plus most dive companies insist on you performing a safety stop.
More Reading: Emergency decompression stop vs safety stop
I hope you enjoyed this article about how deep can you dive without decompression (stops)
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If this article hasn’t answered all of your questions. If you have more questions either about snorkeling or scuba diving (or specifically about how deep can you dive without decompression (stops)), please comment below with your questions.
There will also be many more articles about scuba diving (and snorkeling) for you to read and learn about these fabulous sports.
Have fun and be safe!
More Reading to enjoy: What are the advantages of Nitrox diving?