Wet Riser Pump back up supplies

JameZZZ · Dec 20, 2017

Refurb on an existing building where new wet risers are going in:

Where do changeover switches for back up supplies for wet riser pumps have to be installed? Can they be installed at the main switchboar with a single cable to each pump or does the changeover switch have to ne local to the pump with 2 supply cables? Where are there regs on this?

Also I have been told by fire specialist that the supply has to be able to take the locked rotor current of all fire pumps............I have been told that 2 x 75kw pumps are going in with a LRC of 900 amps each! This seems like an unfeasable requirement ( the existing substation which supplies the building is only 1000KVA). Does this also apply to the back-up generator? Has anyone had this thrown at them before?

Any insights are welcome. Thanks

Pete999 · Dec 20, 2017

What do the drawings and specifications say, surely a job like this can't be done by word of mouth, there must be some paperwork somewhere.

marconi · Dec 20, 2017

http://www.bafsa.org.uk/wp-content/uploads/bsk-pdf-manager/2017/06/BIF-21-Wet-Dry-Risers.pdf

Please see page 3 of 4 of the BAFSA document on wet riser pumps and their power supplies. It does not answer your question completely but there are some contact numbers at the end of it. If they don't know they might be able to direct you to someone who does.

Also IFEDA - the Independent Fire Engineering and Distributors Association.

See: ifeda.org

I'd have thought BS9990 has something to say on the matter.

Lastly: High rise wet riser fire systems installation | UK Dry Risers - http://www.ukdryrisers.co.uk/wet-riser-systems.php

JameZZZ · Dec 20, 2017

Pete999 said:
What do the drawings and specifications say, surely a job like this can't be done by word of mouth, there must be some paperwork somewhere.

There is a spec and drawings (layout only) but the spec says things like “supply to specialists requirements”, and the specialist isn’t committing to much.

JameZZZ · Dec 20, 2017

marconi said:
http://www.bafsa.org.uk/wp-content/uploads/bsk-pdf-manager/2017/06/BIF-21-Wet-Dry-Risers.pdf

Please see page 3 of 4 of the BAFSA document on wet riser pumps and their power supplies. It does not answer your question completely but there are some contact numbers at the end of it. If they don't know they might be able to direct you to someone who does.

Also IFEDA - the Independent Fire Engineering and Distributors Association.

See: ifeda.org

I'd have thought BS9990 has something to say on the matter.

Lastly: High rise wet riser fire systems installation | UK Dry Risers - http://www.ukdryrisers.co.uk/wet-riser-systems.php

Thanks for this BS9990 has basically answered my first question. I will call around to clarify.

Thinking about the LRC problem it may not be so onerous if it is for a very short period of time that this is required....,ie more than the amount of time it takes for the pump to burn out. I will do some more digging.

I appreciate the help.

Pete999 · Dec 20, 2017

JameZZZ said:
There is a spec and drawings (layout only) but the spec says things like “supply to specialists requirements”, and the specialist isn’t committing to much.

Probably doesn't know whats what anyway

marconi · Dec 20, 2017

I think you may need to clarify how the pumps are to be operated ie:

1. Both running at the same time in which case you probably need a scheme for sequential starting one then the other.

2. Master and standby - one nominated to start first and the other only starts subject to some conditions such as perhaps low pressure or Master fails to start in which case standby auto-starts or has to be manually started .

You get the idea.

JameZZZ · Dec 20, 2017

marconi said:
I think you may need to clarify how the pumps are to be operated ie:

1. Both running at the same time in which case you probably need a scheme for sequential starting one then the other.

2. Master and standby - one nominated to start first and the other only starts subject to some conditions such as perhaps low pressure or Master fails to start in which case standby auto-starts or has to be manually started .

You get the idea.

Your right I will seek clarification.
I am pretty sure it is master standby. My concern is that they are asking for supply sized for both pump in LRC condition. I guess the main pump could lock and the standby could kick in then lock as well. Then the problem could clear and the supply would have failed before the pumps. As previously noted I will see if I can find out how long it takes for the pumps to burn out as long as the supply does not break in a shorter time than this I can’t see the point in sizing to LRC for a longer period. Thanks again for help.

marconi · Dec 20, 2017

Would you mind writing another post once you have squared away your questions? It adds to the wealth of knowledge of all of us and our interest - otherwise we are left hanging.

westward10 · Dec 20, 2017

You are dealing with something which could be deemed a safety system. Get an experienced person to design it for you or pass it over. By safety system I mean peoples lives could rely on what you are installing.

JameZZZ · Dec 20, 2017

westward10 said:
You are dealing with something which could be deemed a safety system. Get an experienced person to design it for you or pass it over. By safety system I mean peoples lives could rely on what you are installing.

Whilst I agree with this statement finding someone who does have experience and is willing to commit to anything is proving tricky..... do you know anyone?

JameZZZ · Dec 21, 2017

Update: I have found an excellent guide to this:

BSRIA BG 70/2017 Life Safety and Firefighting Power Supplies

I have not fully read it but it looks like it is going to give me guidance on all my questions.

JameZZZ · Dec 21, 2017

marconi said:
Would you mind writing another post once you have squared away your questions? It adds to the wealth of knowledge of all of us and our interest - otherwise we are left hanging.

Marconi,

Here is what I have found out:

The ATS needs to go by the pump control panels (this is pretty clear in BS9990). This makes sense in terms of better redundancy (2 sets of cables over diverse route). The mains monitoring for generator control should be at the ATS.

As you noted to design the supply you need input on worst case scenarios from the specialist (something I am pursuing). However in very general terms: The mains supply and the back supply need to be designed in accordance with: All the normal stuff you would associate with a motor (starting current, motor rating, efficiency, pf, , starting volt drop, FLC etc.), and the supply and cable must be able to take 150% of the FLC , and it must hold under LRC conditions for 1 pump for 75% of the time it takes for motor burn out. This Basically means appropriately sized BS88 fuses feeding FP600S cables on separate diverse routes feeding the ATS. The fuses need to discriminate with the specialists overloads in the pump starter (I am assuming the specialists overloads need to adhere to all the above as well so I am expecting my fuse and cable sizes to get quite big). Thanks for pointing me in the direction of BS9990. The document which really sorted it for me was BSRIA BG 70/2017 Life Safety and Firefighting Power Supplies.

Bobster · Dec 21, 2017

There may even not be any overloads in place within the starter.

JameZZZ · Dec 21, 2017

Rob said:
There may even not be any overloads in place within the starter.

That would make sense for a pump that you want to run to destruction. I have asked the question of the specialist, along with details of motor burn out time etc. He is going to ask his supplier. I will let you know the outcome if interested.

marconi · Dec 21, 2017

Thank you for taking the time to report back. When I ran the engineering for a strategic site I used parsons brickerhoff to calculate and select high current fuses and circuit breakers and ensure discrimination and trip settings for large motors. They had an electrical modelling tool which could take a design - cbs by make and setting, fuses by make and rating, cables by make and length, load by type and use profile, even ATSs, etcetera and do runs on it to show that an electrical design would perform as required. I used the London office but I note they have an office in Bristol too. Sorry I don't have a contact - it was 15 years ago. So if you design the installation they could do modelling on it and confirm all is well, or they can help you design, source components and test it.

Electrical engineering - http://www.wsp-pb.com/en/WSP-UK/What-We-Do/Services/All-Services-A-Z/Electrical-engineering/

fulminator · Feb 4, 2022

If anyone here has queries regarding sprinkler or wet riser pump installations, the document you need to study is Technical Bulletin 210: 2015: 1.

Lister1987 · Feb 4, 2022

marconi said:
http://www.bafsa.org.uk/wp-content/uploads/bsk-pdf-manager/2017/06/BIF-21-Wet-Dry-Risers.pdf

Please see page 3 of 4 of the BAFSA document on wet riser pumps and their power supplies. It does not answer your question completely but there are some contact numbers at the end of it. If they don't know they might be able to direct you to someone who does.

Also IFEDA - the Independent Fire Engineering and Distributors Association.

See: ifeda.org

I'd have thought BS9990 has something to say on the matter.

Lastly: High rise wet riser fire systems installation | UK Dry Risers - http://www.ukdryrisers.co.uk/wet-riser-systems.php

Snippets from BS990:2015

[ElectriciansForums.net] Wet Riser Pump back up supplies

DPG · Feb 4, 2022

This thread is from 2017.

fulminator · Feb 4, 2022

DPG said:
This thread is from 2017.

Yep, you are right, I just joined today though........ The wiring and monitoring of fire pumps is what I do, have done for decades. My bible is TB 210, just trying to help any electricians out there who may not be familiar. The thread is still extant, isn't it?

westward10 · Feb 4, 2022

fulminator said:
Yep, you are right, I just joined today though........ The wiring and monitoring of fire pumps is what I do, have done for decades. My bible is TB 210, just trying to help any electricians out there who may not be familiar. The thread is still extant, isn't it?

Thread isn't that old welcome to the forum diverse knowledge makes the forum what it is.

DPG · Feb 4, 2022

fulminator said:
Yep, you are right, I just joined today though........ The wiring and monitoring of fire pumps is what I do, have done for decades. My bible is TB 210, just trying to help any electricians out there who may not be familiar. The thread is still extant, isn't it?

Absolutely. Sorry, was just pointing out its age in case you weren't aware.

Welcome to the forum!

freddo · Feb 4, 2022

DPG said:
This thread is from 2017.

Interesting read though.

Here is a photo of a 2 pump set one electric the other diesel. The electric supply had huge fuses for the supply cable size, and no motor overload, just a star/delta starter. 250A FLC. Shame the pump supply cable had been stolen. The diesel pump was awesome. Though the waste storage building this was for was out of use and empty the engine had been serviced somewhat recently. As soon as the start button was pressed it EXPLODED into life, I've never seen a diesel engine start and reach full running speed so fast. You couldn't even hear the starter motors crank the engine it fired so fast. It was fitted with 2 sets of batteries and 2 starter motors for full redundancy, I believe it fired both starter motors together. The water supply tank had the largest ball cock I'd ever seen.

This set may have been scrapped with the rest of the equipment in the building

It was one of the only things there that still worked. Plenty of water spraying out of the heads missing their bubbles!

Lister1987 · Feb 4, 2022

fulminator said:
Yep, you are right, I just joined today though........ The wiring and monitoring of fire pumps is what I do, have done for decades. My bible is TB 210, just trying to help any electricians out there who may not be familiar. The thread is still extant, isn't it?

Correct me if I'm wrong here but thr thread is on Wet Risers pumps, not Automatic Sprinkler pumps, I'm led to believe they are 2 different operating beasts?

loz2754 · Feb 5, 2022

fulminator said:
extant

Nice word. And welcome to the forum.

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