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brazer
10-11-2011, 02:24 PM
Hi,
In England can anyone advise if there is a legal requirement to replace relief valves after a given time frame ( e.g 5 years ).
Have found a lot of info touching on the subject but am getting bogged down & cant find a categorical statement as to whats required.
Thanks in advance
Brazer

taz24
10-11-2011, 03:03 PM
Hi,
In England can anyone advise if there is a legal requirement to replace relief valves after a given time frame ( e.g 5 years ).
Have found a lot of info touching on the subject but am getting bogged down & cant find a categorical statement as to whats required.
Thanks in advance
Brazer

There is a requirement.

The full definitions are in BS EN 378, 2 - 2008

The requirements state that at regular intervals
the valve must be tested and recalibrated to prove to work at +-10% of the maximum working presuure.

The engineer has no accurate way of proving that so it means the valve has to be removed and tested.

Again that means the valve are basicaly removed and replaced.


Copied from the internet.......

Replace pressure relief valves once they have discharged.
Check the nameplate or installation date tag to be sure the time-in-service does not exceed five years.
Look for corrosion and leaks. If there is any doubt about the internal condition of a relief valve, remove and inspect it internally. If there is any question about a valve’s condition, replace it.

All the best

taz.

.

Grizzly
10-11-2011, 10:23 PM
To add.
Your prv test interval is a maximum of 5 yrs and the actual interval is normally decided by the Insurance companies assessor (Zürich are one of the biggest nowadays).
As we have said before whether to replace or O/haul is down to size verses cost.
Very generally put on smaller PRV'S it can be cheaper to just replace.
However there can be quite long lead times in the supply of new, (especially when certs are required).

There decision on timing is related to their written scheme.

Also not all equipment fitted with PRV'S have to be tested.
As in the pressure vessel regs the minimum is 250bar/ Ltrs.

If in doubt check with the site insurers.

brazer
13-02-2012, 10:29 AM
Could anyone advise if there is also a requirement to vent the discharge from PRV's to 'atmosphere' ( i.e out of the plant room).

taz24
13-02-2012, 01:46 PM
Could anyone advise if there is also a requirement to vent the discharge from PRV's to 'atmosphere' ( i.e out of the plant room).

Yes.

The requirements are that the excess pressure is vented outside and not into public areas.

But dependent on the volume of the room and the location of the room inside the building
venting is not always carried outside.

Are you using C02???

C02 requires the PRV to be on the end of the pipe and outside, because of the way high
pressure reacts when it is vented.

All the best

taz

.

brazer
13-02-2012, 03:52 PM
Taz,
Thanks for the reply, no its R134a in a basement plantroom.

hyperion
13-02-2012, 05:56 PM
If the system has a fairly large quantity of refrigerant, it may be worth fitting the special two port changeover shut off valve, as this will allow you to change the PRV in 5 years time without having to take the refrigerant out of the system. Recently fitted these valves to some chillers containing 230kgs of R134A. It will save a lot of time and effort next time.