Car seals 1

[rocketscientist]

As we know, car-sealing is a common term for allowing maintenance for relief valves. Now, I have a client using terms like safety car-seal open and safety car seal closed.

I was wondering if anyone knows any legal definition devining the difference between a car sealed open valve and a safety car sealed open valve?

 

[greenche]

I would expect valves car sealed for safety to have some sort of administrative procedure to document that the process was in a safe condition for the valve to be operated when the car seal is removed. We do not use this term specifically, but we do identify valves on the P&ID that are car sealed in a particular position to allow or prevent flow to a relief valve or vessel through process piping for overpressure protection. These car seals are identified in a procedure as to what specific scenario they are protecting against. If one of these car seals must be removed for maintenance, we use the management of change process to document that it is removed and reinstalled.

 

[pennpiper]

This sounds like a "Client specific terminology preference"

To find out the difference (if there actually is any) you must ask the Client who is using this terminology.

 

[don1980]

"Car-seal open" and "safety car-seal open" are just two ways of saying the same thing.

 

[Latexman]

Maybe they have more than one type of car seal and car seal procedures in their plant, one for safety and one for operations or maintenance. Could be.

Good luck,
Latexman

 

[rocketscientist]

I contacted OSHA directly. They don't have anything to discriminate between a safety car seal and plain car seal.

 

[totallockout]

We could be getting distracted by terms here. 'Car Seal' derives from a device used to 'seal' closed a freight car on the railroads. Nowadays, cargo containers travelling across borders will often be sealed in the same way to provide evidence of tampering with the cargo. This simple seal device has found a new application; to lock valves.

Given that the seal is used for safety reasons, the name has evolved further to 'safety car seal'.

Although car seals can be an effective means to prevent tampering (either inadvertent or deliberate), once the seal is removed, in the case of relief systems, the system can be vulnerable to incorrect sequence of operation.

Various API and ASME codes recognise this hazard and recommend the use of valve interlocks to eliminate this possibility. API RP 520 (Pressure Relieving Systems for Refinery Services - Part II Section 4- Isolation Valve Requirements) and API RP 14E (Design and Installation of Offshore Production Platform Piping Systems - Para 5.8b [2] - Relief Device Piping) specifically recommend interlocks in this situation to ensure that (over)pressure protection of the vessel is not compromised. These recommendations are also in accordance with the requirements of ASME - Section VIII - Appendix M.

 

[SNORGY]

All above is true.

There is, however, a legal difference between "locked open / closed" versus "car sealed open / closed" (e.g. putting a "seal" versus a "padlock" on a plug valve or ball valve. One (car sealing) requires a procedure that is more difficult to "get around" for anyone wanting to "swing the valve for a few minutes and nobody need be the wiser". A padlock can be re-used...a seal with a serial number can't.

Maybe that's the difference that someone was trying to draw attention to in their terminology.

Regards,

SNORGY.