Please Clarify Part L requirements and Zoning small properties

[Mrs Tara Plumbi]

Our company mostly replace boilers so I may be a bit rusty on the requirements for new installations.
But as everyone is talking about heating zones and not just on this forum and we have a quote to do for a new heating system in a tiny property I thought I better read up on the changes.

My first point is I can't see any changes about Zones. Can anyone point me in the right direction? i am looking at Domestic Building Compliance Guide 2010
http://live.planningportal.gov.uk/uploads/br/domestic_building_compliance_guide_2010.pdf Table 2 page 22.

Isn't this exactly the same as the old requirement since (about 2006?)
http://www.planningportal.gov.uk/uploads/br/BR_PDF_PTL_DOMHEAT.pdf This is the 2008 edition of the Domestic Heating Compliance Guide to Building regs 2000 as ammended 2006
Table 2 page 15 appear to be the same.

As you all know it says
..upto 150m2 "should be divided into at least two space heating zones with independent temperature control, one of which is assigned to the living area.
Above 150m2 the 2 space heating zones haveseperate timing and temperature controls.
Weren't the requirements of the smaller dwelling simply met by one stat and TRVs everywhere else?  Has anything changed?
I dug out an old Corgi mag article about exactly this in 2006 and it said TRVs meet the reqirement of independent temperature control - but as ever i may have copied it down wrong.
Further Zoning with extra wiring, controls and pipework would seem madly excessive in tiny homes/ flats.

Thanks in anticipation of brilliant replys.

 

[Mrs Tara Plumbi]

Just adding more info:
Table 2 of first ed May 2006 Domestic Heating Compliance Guide also reads the same about zones and floor area.
It is here http://www.ukwta.org/pdfs/DomHeatingComplGuide.pdf page 15

And in Gas Installer November 2006 Corgi tech support explains how to comply with Building regs pg 51 it says: seperate temperature control of zones within the dwelling - minimum provision is room thermostat or prog. room stat in main living area and trvs on rads in other aeas. ie bedrooms

So my questions are the same: What has changed in oct 2010?
And temperature zones in small properties are still met by room stat + trvs, isn't it?

 

[doitmyself]

The difference is further down the page - Temperature Control of Space Heating!

 

[GrahamM]

Things have not changed for smaller properties.
Best practice is still:
TRV'S IN ALL ROOMS WITH EXCEPTION OF ROOM WITH STAT.
FULL PROGRAMMABLE ROOM STAT.
BOILER INTERLOCK
SYSTEM BYPASS

 

[Mrs Tara Plumbi]

Things have not changed for smaller properties.
Best practice is still:
TRV'S IN ALL ROOMS WITH EXCEPTION OF ROOM WITH STAT.
FULL PROGRAMMABLE ROOM STAT.
BOILER INTERLOCK
SYSTEM BYPASS

thanks, that is my understanding.
BUT the difference is in the tiny small print - thanks DOITMYSELF- I read that and couldn't see the difference. I know lots have missed that because there is much debate in other threads on this forum.

Now i see in 2006 version In table 2 under Temp Control Space heating had point (ii) but that has disappeared in 2010 so it does say room stats in 2 zones AND trvs.
Does this seem too much in little one bedroomed homes?

 

[That Extra Mile]

My understanding on this one is as follows:

All installations now need to be divided into two zones, so effectively a living area and sleeping area. TRVs won't meet the requirements - you'll need two zones controlled by 2-port valves. The only exception is where the living space is over 70% of the total area.

If the property is under 150m2 the two zones must have independent temperature control but can share the same time control. If over 150m2 both time and temperature must be independently controlled.

Have a look at the following:

http://www.worcester-bosch.co.uk/cache/file/23/changes-to-part-l-affecting-new-heating-systems.pdf

A complete pain but that's what the regs say!

One alternative is to use Honeywell's electronic TRVs. They'll satisfy the regs but are expensive (and a bit ugly!)

Jonathan Harris

That Extra Mile ... exceptional heating and plumbing

 

[GrahamM]

Upto 150m² the zoned space only needs independent temperature control ie. one programmable room stat in main zone and TRV's. (TRV's do meet requirements for this) This is what I have read and understood. Any more than that would be ridiculous.
Over 150m² the zones must be independently controllable by switchable controls etc.

If I am wrong you can call me the monkey's uncle.

 

[That Extra Mile]

I wish I was wrong, but don't think I am. TRVs won't do it, sorry. Have a look at this from Honeywell:

http://www.honeywelluk.com/Documents/All/pdf/1173.pdf

This new regulation is total madness!

Jonathan

 

[Kimou]

.....

 

[franz]

hi KIMOU.if your bored go and watch desperate houswives, but dont bother posting rubbish.
regards

 

[GrahamM]

I stand by what I have stated. I have just read through 100 odd pages of "domestic building compliance guide 2010" to confirm, which states as I have said above. Unless my eyes are deceiving me I am correct. Don't be passing the bananas yet.
I believe the honeywell document is slightly miss-aligned in its information.

 

[doitmyself]

I stand by what I have stated. I have just read through 100 odd pages of "domestic building compliance guide 2010" to confirm, which states as I have said above. Unless my eyes are deceiving me I am correct.

You should go to Specsavers!

The difference is very subtle:

Compliance Guide 2008 says (Page 15, Table 2):

Temperature Control of Space Heating

Separate temperature control of zones within the dwelling, should be provided, using:
i. room thermostats or programmable room thermostats in all zones; or

ii. A room thermostat or programmable thermostat in the main zone and individual radiator controls such as Thermostatic Radiator Valves (TRVs) on all radiators in the other zones; or

iii. a combination of (i) and (ii) above.

Compliance Guide 2010 says (Page 23, Table 2):

5.0 Temperature Control of Space Heating
Separate temperature control of zones within the dwelling, should be provided, using:

i. room thermostats or programmable room thermostats in all zones; and

ii. individual radiator controls such as Thermostatic Radiator Valves (TRVs) on all radiators other than in reference rooms (with a thermostat) and bathrooms.


The 2010 Guidance is effectively option (iii) of the 2008 Guidance.

Two (programmable) thermostats by themselves is no longer allowed
One (programmable) thermostat + TRVs is no longer allowed

Two (programmable) thermostats + TRVs are required.

The rules on time controls have not changed: Up to 150m² you can have a common time control for both zones; over 150m² you must have separate time control for each zone.

What is not so clear - I found it somewhere - is that this applies to each 150m². So a house which is over 300m² will need three zones; over 450m² it will need four zones

 

[Kimou]

Deleted. Just a little fun. Don't wanna cause a hooha

 

[GrahamM]

OK! Pass the bananas- where's the nephew? Missed last part of the table 2- section 5. You really have to read the whole lot to get the full picture. All a lot of nonsense anyway.
Ridiculous that a small dwelling now has to have 2 room stats.