Part L Building Regs.

[Daddy Cool]

Can anyone explain how this works....Part L of the building regs states that 'fan coils' should have a specific fan power no more than 0.8w/l/s (other items are listed) but how does this relate to VRF/VRV; Multi split etc ducted fancoils? do they have to comply, and if not, why not, what defines a 'fancoil':confused: The system i want to use is neither of the above, but similar to both, but i need to know how it fits in with Part L.

Any ideas?

[eggs]

Good morning Daddy.

I'll have a go!!!

SFP= energy consumption in W / air flow in l/s

My understanding is this for example:

A 7kw Tosh indoor unit has a power consumption of 60w and a max air flow rate of 317 l/s so....

60/317= 0.19 (it qualifies)

Regards

eggs

[multisync]

Does it not qualify automatically if it's on the ECA list?

Multisync
London

[Daddy Cool]

Thanks for your responses gents.

Eggs, I took the biggest ducted fancoil (in this case an Hitachi as it was the first tech manual I picked up) and worked the SFP, and it was over the 0.8w/l/s. Daikin are over on their 8HP, but scrape in on the 10HP. The bit I find strange and makes me think I’m missing something is that none of the VRF manufacturers make claims to comply with this section of Part L anymore than they claim that they comply with Part M as it has no relevance to them.

Multi, I’m really not sure about the ECA, it’s not mentioned in Part L as being a pre-qualification or alternative but who knows?

[Grizzly]

Good morning Daddy.

I'll have a go!!!

SFP= energy consumption in W / air flow in l/s

My understanding is this for example:

A 7kw Tosh indoor unit has a power consumption of 60w and a max air flow rate of 317 l/s so....

60/317= 0.19 (it qualifies)

Regards

eggs
Based on what you have explained eggs.
Thats 1 hell of a sized plant before it fails or have I got the "wrong end of the stick"
Grizzly

[eggs]

Yes you are correct Grizzly.
A 28kw high static Tosh indoor fails. with 0.9.
This is if it is the only fcu in the building. If the previous 7kw was also installed in the building, the average is used for Part L compliance.

ie SFP 0.9 + SFP 0.19 = SFP 0.545.

Simple eh....!!

On these big Fcu's, ie the 28kw ones it think it could be argued that it is classed as HVAC plant which has an allowance of SFP 2.5.

Cheers

eggs

[Daddy Cool]

That's where the problems start, table 35 (or 36 in existing buildings) list system types, but don't define the criteria clearly, they generically refer to fan coil units, but don't give any method of identification. It looks like half-baked legislation that is open to the building control officers’ individual interpretation of meaning. I see they also refer to BS EN 13779, which has a list of tables from SFP 1 through to SFP 6, but I can't find what identifies each category without paying a fortune for the standard. Most frustrating.

[Daddy Cool]

Hi Grizzly,

Don't be deceived, a fairly small 4 pipe fan coil from many well known manufacturers just slip inside the limits. A small fancoil 2.12kW Sens duty, 193l/s, but 161W, so SFP = 0.834, over the limit. Most get their numbers down by using EC/DC fan motors.

[Daddy Cool]

The plot thickens; i decided to speak to my local building control officer to get some form of direction, after a very large groan at what must have seemed like a very tedious technical question, they basically said 'don't know...don't care' they use the SBEM for the entire building to show a pass/fail and are not interesting in the individual components of the system. Still non the wiser though???

[eggs]

they basically said 'don't know...don't care'

:D which is why i give up and presented them with pages and pages of worthless calculations:D

They knew (and cared) less than me about it all.

Eggs

[Daddy Cool]

I was talking to a top AHU bloke today, and asked his take, he basically said they find the 'sweet spot' for the 'system' with the best efficiency and issue that, so even if that falls at 30Pa and 200 l/s but in reality it will be running at 6M³/s and 800Pa they just offer the 'ideal' results.

I supose the moral of the story is give them what they want to see?

The only obsticle i have now is a pain in the butt consultant........

[eggs]

I supose the moral of the story is give them what they want to see?


Yes Daddy Cool, it's what Sir Alan Sugar would call "A Mugs Eyefull"
Leaves the privatley unemployable, public sector fools baffled

;)

eggs