visual inspection after hydro

[superstar]

I was told by my LDS the other day that it is possible that my tank can pass a hydro test but then fail their VIP test. I can buy the fact that they may be checking for water left in the tank but the story I am getting is the integrity of the VIP testing process is much better than the hydro test. And he kept a strait face.

 

[adelman]

There is a visual inspection done as part of the hydro, but it is to a different set of standards than the Scuba industry Visual Inspection.

The hydro re-qualification visual inspection doesn't include an inspection of the valve; the scuba industry inspection does.

The hydro re-qualification visual inspection permits surface corrosion provided it isn't going to mask pitting or other corrosion that would cause a fail. The scuba industry visual inspection is more likely to reject a cylinder until the corrosion is cleaned up.

The hydro re-qualification doesn't care about the Oxygen-clean status of the cylinder and may even contaminate the cylinder.

BUT... is the second inspection to a different set of criteria really necessary? The rest of the compressed gas industry seems to do fine without it...

 

[BoltSnap]

I was told by my LDS the other day that it is possible that my tank can pass a hydro test but then fail their VIP test. I can buy the fact that they may be checking for water left in the tank but the story I am getting is the integrity of the VIP testing process is much better than the hydro test. And he kept a strait face.

Hydro and Cylinder Visual Inspection (according to PSI standards) are totally different tests. Each test is concerned with a different set of metrics for determining if the scuba Tank is passable or not.

When a client brings in a Tank for hydro, we do a VCI first (without written report or sticker) to make sure that the Tank is passable before we send it out to the Hydro testing facility. We'd do the formal VCI again after the Tank is returned from the hydro testing facility. We do the first VCI to save the customer money if his Tank wouldn't pass the VCI, since there is point of sending it for hydro testing if it would fail a VCI.

We charge the customer for only 1 VCI.

In short, your LDS is doing his job and is following local standards including "community standards." I am assuming that your LDS has a certified PSI inspector to do the visuals.

I'd recommend that you do a full valve O/H including changing the burst disc along with tank hydro/VCI.

 

[duckbill]

The hydro re-qualification visual inspection doesn't include an inspection of the valve; the scuba industry inspection does.

I once had a dive shop owner say my cylinder/valve would have to be condemned because the valve didn't have at least three threads showing And this was for a regular annual visual. Not "fail, "condemn". If you are going to include the valve as part of your visual, please at least know what you are talking about. Just a pet peeve of mine due to that incident.

 

[superstar]

BurhanMuntasser
What are the local and community standards?

 

[owlbill]

FWIW, I have had an AL cylinder pass hydro with no less than 2 full cracks running the full length of the threads. a VIP pre and post hydro is a good idea in my opinion. I don't however think the customer should be charged twice. 1 x VIP and 1 x HYDRO (unless the hydro cost includes the VIP) is all that should be charged.

 

[akdeepdiver]

Our Hydroshop does a Pre and post Hydro Visual inspection. We do them to PSI protocals. We also rebuild the valves at this time. All for one low price of $40. This is why all the dive shops in my area are my customers. Plus they love our complimentry pickup and drop off service.

 

[redacted]

Our Hydroshop does a Pre and post Hydro Visual inspection. We do them to PSI protocals. We also rebuild the valves at this time. All for one low price of $40. This is why all the dive shops in my area are my customers. Plus they love our complimentry pickup and drop off service.

Does your hydro shop apply a VIS sticker? Do your dive shop customers charge their divers for another visual?

 

[Doc Harry]

Hydro is a dirty process. A visual inspection after hydro is mandatory in my opinion.

The inspection after hydro is really just a continuation of the pre-hydro inspection.

I agree that you should be charged for only one VIZ.

 

[DA Aquamaster]

There are pros and cons. For what ever reaosn the DOT seems to be ok with the visual inspection done at requalification being done prior to the hydro test. I have however seen previously unobserveable cracks in 6351-T6 alloy tanks propoate during the hydro test to the point they were now detectable. That argues for a post hydro VIP and visual eddy, not one done prior to the test. In my opinion, the only advantage of doing the VIP first is to exclude the a tank that wil fail from the entire hydro test procedure.

But, crack issues aside, as noted in other posts above, it is imperative to at least look in the tank post hydro test to ensure it is dry and does not contain foreign objects, visible contaminants or excessive flash rust or corrosion.

So unless the shop knows that the test facility does this and then properly seals the tank toprevent contamination, the LDS needs to do a VIP and at a minimum at least needs to peak inside.

Charging for that additional VIP is a separate issue. The LDS will be marking up the cost of the hydro (probably 100%, so they are already making money on it and they will be making money on the fill. Given that the scope of their VIP in this context is less, that the cost of the VIP sticker itself is minimal and that they have already made money off the hydro and VIP done as part of the requalification, it is gouging the customer to look in the tank to ensure it is dry, non rusted/corroded and has no visible contaminants, and then slap a sticker on it.

A legitamate exception here is I think 6351-T6 tanks given the potential that the hydro test is done after the VIP at the hydro facility and that a crack could be present post hydro test.

O2 cleaning is also a separate issue with separate tolerances for a VIP. For example, given the isses with entrained particles I won't tolerate any flash rust in an O2 clean tank, but would not worry about it during the VIP of a tank to be used with air only provided it had not progressed to the point where it may prevent proper inspection of the tank, hide pitting, or concentrate moisture and promote pitting.