IP creep-when to repair and when to ignore

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Before you creeps drift too far off-see SP Bulletin 242.

I'm pretty confident that SP just didn't want to put the words " acceptable creep" into a service bulletin.

These 1st stages, because of the new seating configuration, might have a tendency to drift upon pressurization. This is normal for these 1st stages. Please follow the guidelines below for what we consider to be an acceptable drift.

"Drift" is a little bit of a euphemism for IP creep in this bulletin, IMO.

But, sure, it's basically playing with words. Peter Wolfinger basically uses the term 'drift' to describe 'creep' in reg savvy. (He uses parentheses (like me!) to indicate this) Vance Harlow uses the terms as separate specific problems:

Sometimes the IP will drift rather than creep. That is to say, it will stop cleanly, but at a slightly different pressure each time.

To me this is more useful, because you have specific terms to describe specific problems.
 
Sometimes the IP will drift rather than creep. That is to say, it will stop cleanly, but at a slightly different pressure each time.

To me this is more useful, because you have specific terms to describe specific problems.
I agree with Vance's definition; I agree with you that it is more useful to use different terms to describe specific (and different) problems. I'm sure you will agree that other's who use the terms in the same manner as used in certain ScubaPro documents can be forgiven. ;-)
 
Boy, when I started this thread I never realized how the opinions would go. In my book and an engineering point of view, creep and drift are the same. The principal issue is whether it is self-limited or continuous. My original question was not about continuous which is absolutely unacceptable but rather how much rise and what percentage of the total span of working pressure to an endpoint is acceptable.
 
Boy, when I started this thread I never realized how the opinions would go. In my book and an engineering point of view, creep and drift are the same. The principal issue is whether it is self-limited or continuous. My original question was not about continuous which is absolutely unacceptable but rather how much rise and what percentage of the total span of working pressure to an endpoint is acceptable.
Didn’t we all say the same thing?:wink:
 
I have 12 MK25s. It is time to service them and I can get 11 of them to lock-up at 140 psig, which is where I like to put them. However, I have 1 that when set at 140, it will creep over the next 5 minutes to 145 psig and stop. Before I throw another piston or HP seat at it, at what point am I just obsessing over it? Opinions or suggestions. I do not see anything that could be causing this problem from looking at both the seat and the piston edge. Any chance the spring under the HP seat could be the problem with it always wanting to go the 145 psig? Thanks!

JC...

Mosey-on-up...creep...drift...all means ''leak''

A nick in the knife edge...a scored or off level HP seat...careless/unclean installation protocols...bad ''O'' rings...

Zero is what it should be...zero is what your striving for...if it's leaking pre service...and leaking post service...you are accomplishing nothing...and spending $$$ to do it...

We're back to discussing minimum standard...and equal to...or greater than...I prefer greater than...just as I prefer scuba gear that doesn't ''leak''...over scuba gear that does leak...

Just me...

Warren
 
JC...

Mosey-on-up...creep...drift...all means ''leak''

A nick in the knife edge...a scored or off level HP seat...careless/unclean installation protocols...bad ''O'' rings...

Zero is what it should be...zero is what your striving for...if it's leaking pre service...and leaking post service...you are accomplishing nothing...and spending $$$ to do it...

We're back to discussing minimum standard...and equal to...or greater than...I prefer greater than...just as I prefer scuba gear that doesn't ''leak''...over scuba gear that does leak...

Just me...

Warren
I have to point out that since some manufacturers actually specify an allowable range of drift or creep, that indication of a fault or defect is NOT always the case when it exists, as long as it locks up within spec.
 

Back
Top Bottom