RE: Re: [PSUBS-MAILIST] Isn't 'Mini book review.' anymore--pressure test

[Alec Smyth <Asmyth@changepoint.com>]

Not really... to complete your example:

- Design to 200
- Test to 150
- Use to 100

In the archives you'll find discussions about what the actual ratios should
be, but the basic idea is safety factors are still only theoretical. You
still want to KNOW the sub will go deeper than you are actually go. 

Alec

-----Original Message-----
From: rjune@fuse.net [mailto:rjune@fuse.net]
Sent: Thursday, April 11, 2002 2:41 PM
To: personal_submersibles@psubs.org
Subject: Re: Re: [PSUBS-MAILIST] Isn't 'Mini book review.'
anymore--pressure test


why all the comotion about tank testing a sub.

I think it would be more wise to desighn/buld a sub
for 2 times the intended depth (say 200 meters).
and ony use it at the intended depth (100 meters).
isn't that what safty factors are all about.


> 
> From: William Alford <walford@dbtech.net>
> Date: 2002/04/11 Thu PM 12:53:40 EDT
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] Isn't 'Mini book review.'
>   anymore--pressure test
> 
> At 10:24 PM 4/10/2002 -0700, you wrote:
> >I'm less concerned with generating the pressure on a vessel filled with
> >water, actually, and more concerned with sealing a big tank with a door
in it.
> 
> on the topic, Hyperbaric therapy chambers are often tested by filling with
> water and then pressurizing with air, however, the above concern of
sealing
> a big tank with *big* door is paramount. Consider that a 30" door of a
HBOT
> chamber pressurized to only 2 atmospheres has a cumulative pressure (add
up
> all those PSI's on the entire area) on the door of around 5 tons! which is
> equivalent of a dive to only 33 feet of seawater. A testing tank failure
at
> the pressures for modest psub depth and the required diameter of a door
(or
> flange mechanism) for sub admittance could be catastrophic. There is a
> report in "Hyperbaric Facility Safety"- WT Wortman, of a 30" door failure
> blowing off the HBOT chamber and through the wall of the building and
> killing someone in the next room. Of course it was filled with O2, not
water. 
> 
> The construction challenges of an enormous test chamber might rival that
of
> the psub itself.
> 
> William Alford
> walford@dbtech.net
> 
> Tout comprendre c'est tout pardonner
>