What is the 130 rule?

[vcblklion]

I remember having a conversation with an L.A. County instructor after I had just taken my PADI Nitrox certification about whether I had been taught the 130 rule. I had not been but now I do not remember what he explained the rule was. Can someone explain to me what the 130 rule is as it relates to Nitrox?

Thanks so much!

 

[live_2_dive]

He was probably referring to the recreational dive limits being 130'.


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[vcblklion]

This was specifically in regards to Nitrox training.....

 

[mathauck0814]

Max Depth + Runtime > 130 minutes = No Decompression Diving, on 32%, as I understand it.

More of a guideline than a rule. Not sure why it's helpful, but I've heard other divers refer to it.

 

[vcblklion]

Runtime...? is that the same as total bottom time?

 

[DA Aquamaster]

It probably refers to the NOAA 32% NDLs:

• 130ft 20 min
• 120ft 25 min
• 110ft 30 min
• 100ft 30min
• 90ft 40min
• 80ft 50min
• 70ft 60min
• 60ft 100min
• 50ft 200min

You need to exclude the deeper 110'-130' depths where it overly shortens the NDL as well as the longer 50' and 60' limits where it again overly shortens the NDL, but otherwise if you are diving between 70 and 100 ft where 32% is commonly used/makes the most sense and you subtract your current depth from 130 you get the NDL for that depth.

If for example you are at 90 feet and you subtract 90 from 130, you get 40 - the NDL for that depth.

 

[vcblklion]

Max Depth + Runtime > 130 minutes = No Decompression Diving, on 32%, as I understand it.

More of a guideline than a rule. Not sure why it's helpful, but I've heard other divers refer to it.

So I'm not following....if my Max Depth = 70ft + "Runtime" = 45min = 115min?? means I need to Deco??? I'm confused...sorry..

---------- Post Merged at 02:57 PM ---------- Previous Post was at 02:55 PM ----------

It probably refers to the NOAA 32% NDLs:

• 130ft 20 min
• 120ft 25 min
• 110ft 30 min
• 100ft 30min
• 90ft 40min
• 80ft 50min
• 70ft 60min
• 60ft 100min
• 50ft 200min

You need to exclude the deeper 110'-130' depths where it does not work as well as the longer 50' and 60' limits where it also does not work, but otherwise if you are diving between 70 and 100 ft where 32% is commonly used/makes the most sense and you subtract your current depth from 130 you get the NDL for that depth.

If for example you are at 90 feet and you subtract 90 from 130, you get 40 - the NDL for that depth.

Oh...ok..that sounds reasonable...

 

[JohnN]

It probably refers to the NOAA 32% NDLs:

• 130ft 20 min
• 120ft 25 min
• 110ft 30 min
• 100ft 30min
• 90ft 40min
• 80ft 50min
• 70ft 60min
• 60ft 100min
• 50ft 200min

You need to exclude the deeper 110'-130' depths where it overly shortens the NDL as well as the longer 50' and 60' limits where it again overly shortens the NDL, but otherwise if you are diving between 70 and 100 ft where 32% is commonly used/makes the most sense and you subtract your current depth from 130 you get the NDL for that depth.

If for example you are at 90 feet and you subtract 90 from 130, you get 40 - the NDL for that depth.

I get a PO2 =1.58 for EAN 32 @ 130 feet. . . A little 'sporty' for me. . .

 

[mathauck0814]

So I'm not following....if my Max Depth = 70ft + "Runtime" = 45min = 115min?? means I need to Deco??? I'm confused...sorry..

Notionally, if you wanted to do a 45 minute dive to a max depth of 70 ft on 32% then you would still be safely within your no decompression limits.

70 feet + 45 minutes = 115.

115 > 130 = NDL > 0

 

[vcblklion]

115>130 115 is not GREATER than 130...it's less. or 115 < 130