IANTD tables

Sutty · 29th March 2006, 20:22

A bit of an admission of inadequacy here...

Before getting CCR training a year ago I was trained on OC entirely with BSAC. As a result I was familiar only with BSAC tables.

Since my course I've been diving with my VR3 ( and a backup timer). Dives with no or only a short deco, checked a few scenarios in simulate on the VR3 to check bail out for if I have to go O/C and the VR3 fails.

I have a set of IANTD constant PO2 1.2 air dil tables but am not really familiar with IANTD tables.

The no-deco limit bit is obvious, as is the deco for single dives, with a surfacing "repetitive group" (RG), this evidently then declines with surface interval eg from K to D after 3hrs. This is then translated to a "residual nitrogen time" which varies with the depth of the subsequent dive.

I'm not completely clear what you do with this "residual nitrogen time" I presume that you add it to your next dive's bottom time to plan your deco but would like confirmation that this is correct. eg RG=K after 1st dive, 3hr20 surface interval changes this to RG=D, next dive planned to 30m max so Residual Nitrogen Time = 12min.
This would mean that 2nd dive of 40min at 30m, use deco as if bottom time 40+12=52min so use 30m 55min table.

If someone can confirm or correct this I'd be grateful.

Many thanks,
Neil

Sorry for being a numpty, but I'd rather ask than live on in ignorance!

mattmexico · 30th March 2006, 01:04

yo

Them tables work like all IANTD tables, and you are right. The residual nitrogen time from the previous dive is added to the bottom time of the next dive, with that you go into the table either no deco or deco and that gives your new pressure group and deco info if you are on the deco side. If you want to know how much non decompression limit you still have for the next dive you take the residual nitrogen time away from the original max no deco limit and that is your remaining no deco limit for the next dive.

IANTD has as well some constant 1.2 po2 tables for I believe 3 trimix mixtures, they have as well a otu - cns tracking table from the same material and an instructor set with all the exercises a student has to do which i have found helpfull to get the rust off when not in the water with a ccr for some time

Matt

***diverklondike*** · 30th March 2006, 01:43

The constant PPO2 tables are excellent!!! They are based on VPM-B.

I always carry them with me for bailout purposes etc...

Dive Safe...

Mark

***ScubaDadMiami*** · 30th March 2006, 05:49

Quote: (Originally Posted by diverklondike)

The constant PPO2 tables are excellent!!! They are based on VPM-B.

I always carry them with me for bailout purposes etc...

Dive Safe...

Mark

I also have a set. They are based on V-Planner on a nominal setting (says so on the tables).

29th March 2006, 20:22	#1 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 775	IANTD tables A bit of an admission of inadequacy here... Before getting CCR training a year ago I was trained on OC entirely with BSAC. As a result I was familiar only with BSAC tables. Since my course I've been diving with my VR3 ( and a backup timer). Dives with no or only a short deco, checked a few scenarios in simulate on the VR3 to check bail out for if I have to go O/C and the VR3 fails. I have a set of IANTD constant PO2 1.2 air dil tables but am not really familiar with IANTD tables. The no-deco limit bit is obvious, as is the deco for single dives, with a surfacing "repetitive group" (RG), this evidently then declines with surface interval eg from K to D after 3hrs. This is then translated to a "residual nitrogen time" which varies with the depth of the subsequent dive. I'm not completely clear what you do with this "residual nitrogen time" I presume that you add it to your next dive's bottom time to plan your deco but would like confirmation that this is correct. eg RG=K after 1st dive, 3hr20 surface interval changes this to RG=D, next dive planned to 30m max so Residual Nitrogen Time = 12min. This would mean that 2nd dive of 40min at 30m, use deco as if bottom time 40+12=52min so use 30m 55min table. If someone can confirm or correct this I'd be grateful. Many thanks, Neil Sorry for being a numpty, but I'd rather ask than live on in ignorance! __________________ Never forget that life is a finite resource. Last edited by Sutty : 29th March 2006 at 21:53. Reason: Spelling & clarity
(Offline)

30th March 2006, 01:04	#2 (permalink)
mattmexico Rebreather World Writer Current Rebreather/s: Megalodon Classic Kiss Optima RB80 / Clone Other Rebreather/s: Inspiration Classic Evolution Prism Topaz Sport Kiss RB80 / Clone Join Date: Aug 2005 Location: Mexico, Q.Roo, Playa del Carmen Posts: 736	Re: IANTD tables yo Them tables work like all IANTD tables, and you are right. The residual nitrogen time from the previous dive is added to the bottom time of the next dive, with that you go into the table either no deco or deco and that gives your new pressure group and deco info if you are on the deco side. If you want to know how much non decompression limit you still have for the next dive you take the residual nitrogen time away from the original max no deco limit and that is your remaining no deco limit for the next dive. IANTD has as well some constant 1.2 po2 tables for I believe 3 trimix mixtures, they have as well a otu - cns tracking table from the same material and an instructor set with all the exercises a student has to do which i have found helpfull to get the rust off when not in the water with a ccr for some time Matt __________________ N 20' 37.617' W 87' 04.693' www.andreaswmatthes.com
(Offline)

30th March 2006, 01:43	#3 (permalink)
*diverklondike* Moderator Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Oct 2005 Location: Delaware, USA Posts: 1,458	Re: IANTD tables The constant PPO2 tables are excellent!!! They are based on VPM-B. I always carry them with me for bailout purposes etc... Dive Safe... Mark
(Offline)

30th March 2006, 05:49	#4 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 1,927	Re: IANTD tables Quote: (Originally Posted by diverklondike) The constant PPO2 tables are excellent!!! They are based on VPM-B. I always carry them with me for bailout purposes etc... Dive Safe... Mark I also have a set. They are based on V-Planner on a nominal setting (says so on the tables). __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode