Safety butterfly valve to shut off a penstock fl

Good evening everybody.

I’m an electrical engineer and I have a safety question regarding a safety butterfly valve that closes automatically after an excess flow detection.
I’m familiar with these systems and, if the valve does close, I think it’s mandatory that the reset is always a manual operation and performed at the valve premises.

I have a contractor that doesn’t agree with this approach and asks what regulation document supports our understanding.
What document should be followed?

Thanks for your help.

Carlos Melim
 
Boa noite,

Está bem?

If you're the Customer, your understanding is what the contractor must adhere to. If you have other facilities that are configured as you indicate, then that's your Company's requirement.

I have seen a very similar implementation for other power generators that are remotely operated. When a serious condition occurs a lock-out is latched and a site visit is required to investigate the issue before the latch can be reset and the unit re-started and put back in service. This is usually an OEM (Original Equipment Manufacturer) requirement, usually driven by warranty. I have seen some owners/operators which did away with this scheme; and I know of one site that "cratered"a machine because the problem wasn't properly identified "remotely" before restarting.

A lot of people in the automation industry believe that just because something is possible it is acceptable and safe. And, of course, no one wants their control system to be perceived as difficult or unreliable, requiring a manual site visit to return to operation. But, some conditions SHOULD be humanly and personally investigated before putting the equipment back in service. If it's an instrumentation issue, then fixing the instrumentation will prevent another site visit. If it's an actuator issue or a valve issue (binding; something preventing excess opening)--it should also be fixed before just resetting the alarm remotely and another--possibly catastrophic--problem occurs.

Again, if it's your Company's equipment your wishes are the rule.

Automation is not always the best answer to every problem. Regardless of the size of the equipment (large or small). And, with the water issues in some places in the world (mainland Portugal, for example) wasting water is NOT a good thing (actually, wasting natural resources is NEVER a good thing).

Até já!
 
As a general rule, protection against overflow is achieved by an electrically/pneumatically controlled valve, protection against overpressure is achieved by a Slam Shut Valve [or similar] which cannot be reset except by a manual operation and performed at the valve premises:
https://valves.bakerhughes.com/moon...elivering-accuracy-performance-and-protection

As indicated above post, everything else depends on application. There is very little legislation on this - the UK has '1998 installation and use' regulations but this is for domestic applications.

You could regard industrial use as self-regulating and would expect every gas related project to have a HAZOP [or similar] review to iron out end user circumstances. So for overflow, it could be automated reset or manual operation and performed at the valve premises. Everyone involved needs to accept liability [although this tends to commercially fall on the main contractor], and for that reason for very large / critical applications it is not unusual to have an insurance company representative to attend the above review.
 
Boa noite,

Está bem?

If you're the Customer, your understanding is what the contractor must adhere to. If you have other facilities that are configured as you indicate, then that's your Company's requirement.

I have seen a very similar implementation for other power generators that are remotely operated. When a serious condition occurs a lock-out is latched and a site visit is required to investigate the issue before the latch can be reset and the unit re-started and put back in service. This is usually an OEM (Original Equipment Manufacturer) requirement, usually driven by warranty. I have seen some owners/operators which did away with this scheme; and I know of one site that "cratered"a machine because the problem wasn't properly identified "remotely" before restarting.

A lot of people in the automation industry believe that just because something is possible it is acceptable and safe. And, of course, no one wants their control system to be perceived as difficult or unreliable, requiring a manual site visit to return to operation. But, some conditions SHOULD be humanly and personally investigated before putting the equipment back in service. If it's an instrumentation issue, then fixing the instrumentation will prevent another site visit. If it's an actuator issue or a valve issue (binding; something preventing excess opening)--it should also be fixed before just resetting the alarm remotely and another--possibly catastrophic--problem occurs.

Again, if it's your Company's equipment your wishes are the rule.

Automation is not always the best answer to every problem. Regardless of the size of the equipment (large or small). And, with the water issues in some places in the world (mainland Portugal, for example) wasting water is NOT a good thing (actually, wasting natural resources is NEVER a good thing).

Até já!
Boa noite.

Muito bom cruzar-me com quem fala português.

Thanks for your quick reply.

I work for a Portuguese utility and all our hydro plants are equipped with safety shut off valves, not remotely resettable.

It this, in fact, an utility requirement.

I was just searching if there is a regulation that foresees that requirement.

The regulation would guarantee a correct framework of the issue.

Stay safe.

Abraço desde Portugal.
 
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