Noise requirements and planning consent

[JamesPa]

Has anyone had any experience of the noise considerations in relation to planning consents.  The MCS 020 rules (and therefore the rules for 'deemed consent') appear to impose rather severe constraints on location unless one of the following apply

 

• you pretty isolated from your neighbour
• you are able to site the unit so there is only one reflective surface within a metre
• there is a physical barrier between the unit and the neighbour such that the relevant points in the neighbour's property are invisible

 

For example, for a unit with a fairly typical sound power level of 60dBA (many units are more, some are less), where the unit is mounted on the ground within 1m of a wall (or on the wall within 1m of the ground) the minimum permissible distance (according to MCS 020) from the unit to the nearest 'assessment point' (basically a point 1m in front of the centre of your neighbours nearest, or most affected, window), is 8m unless the assessment point is invisible from the unit.  That's quite an ask even in more spaced out residential areas, particularly where neighbours have extended to the max.

 

So my question is - if you apply for planning consent as opposed to trying to sneak in with deemed consent, do more relaxed rules tend to apply, or is it really this difficult?  Having completed most of the rest of my system design I'm now struggling to find a suitable location, and I live in a 1930s detached house in a leafy road (= well spaced properties).   If this is truly the case I'm struggling to see how the current generation of ASHPs are going to work in many smaller, more densely packed properties.

 

FYI the table below shows the figures I am using, the body shows the max permissible sound power level to meet MCS020 at various distances from the 'assessment point'.

 

Any comments/experience welcome.

 

 

----------------------------------------

(example above in red)

 

Max permissible sound power level (dBA) to meet MCS020
Visible	3m	4m	5m	6m	8m
Q1 One reflective Surface	54	57	58	60	63
Q2 Two reflective surfaces	51	54	56	57	60
Q4 Three reflective surfaces	48	51	53	54	57
Partial View
Q1 One reflective Surface	59	62	63	65	68
Q2 Two reflective surfaces	56	59	61	62	65
Q4 Three reflective surfaces	53	56	58	59	62
No view
Q1 One reflective Surface	64	67	68	70	73
Q2 Two reflective surfaces	61	64	66	67	70
Q4 Three reflective surfaces	58	61	63	64	67

[JohnMo]

Not sure you have done the calculations.

 

See attached calculation sheet.

MCS-020.pdf

[JamesPa]

I did the calculations using the MCS downloadable spreadsheet!

[Dave C]

Mm, I think your calculations are correct - a 60dBA heat pump that's only 6m away from the assessment point attracts a -20 adjustment, so 40dBA, which then gets a +3 correction pushing it over the 42dBA allowed level, i.e. you need to be further than 6m away, and the next level is 8m distance.

 

Something that might help is the rule on barriers: if you have a 2m fence on your garden, it entirely blocks line of sight to all neighbouring ground floor rooms (they don't count anyway if they're kitchens, but the fence gives a large adjustment that makes it trivial to come in under the limit). If the heat pump is just over 1m from the fence, the fence is far enough away it doesn't increase the Q factor, but it may still block line of sight enough to their first-floor bedrooms to get you the -5dBA adjustment for obscured line of sight ... now you only need to be 5m away, which considering you're measuring to a first floor room so you have the added height, is probably quite plausible. That may be how my installation skated in under the rules (assuming the installers actually ran the calculation correctly in the first place, which I suppose is not guaranteed!).

Edited September 5, 2022 by Dave C

[Nick Thomas]

I was a bit worried about mine, although not as worried as the neighbours 😅 . The calculations snuck in at 42 dB(A), and in practice it's fine - if I go to either side of the garden, it's barely audible. Haven't caught the neighbours yet, but I assume they'll be compelled to agree.

 

* It's a 65dB(A) heat pump (grant 6kW)

* "two reflective surfaces"

* "Partial barrier" (scratty garden fence)

* "Assessment position" 8 metres (somehow - it's in the middle of a 9M wide garden with neighbours on both sides, detached in name only)

 

A mid-terrace from the same developers would probably not come in under the limit.

 

Really, it's a bit weird to have one per house. It's a shame district heating isn't more widespread.

[JamesPa]

10 hours ago, Nick Thomas said:

I was a bit worried about mine, although not as worried as the neighbours 😅 . The calculations snuck in at 42 dB(A), and in practice it's fine - if I go to either side of the garden, it's barely audible. Haven't caught the neighbours yet, but I assume they'll be compelled to agree.

 

* It's a 65dB(A) heat pump (grant 6kW)

* "two reflective surfaces"

* "Partial barrier" (scratty garden fence)

* "Assessment position" 8 metres (somehow - it's in the middle of a 9M wide garden with neighbours on both sides, detached in name only)

 

A mid-terrace from the same developers would probably not come in under the limit.

 

Really, it's a bit weird to have one per house. It's a shame district heating isn't more widespread.

 

'In the middle of a 9m wide garden' sounds potentially like a long external pipe run.  I have been trying to avoid that (10m seems the generally accepted max).  Can you elaborate on location, pipe run length etc and also what its like nearby and inside.  

[Nick Thomas]

Sorry, should have been clearer. The garden is 9M wide and about 10M long, with the house running along the width of it. The heat pump is butted up right against the house (under the kitchen window), but placed about 4.5M away from each of the two sides, i.e., at (4.5,0). It's not located centrally in the garden, i.e., at (4.5,5.0) 😅

 

The installers said the pipe run could be up to 10M. The pipes go straight up the house to the first floor bathroom and pass under the bath to get to the airing cupboard. So that's under 5M of pipe length.

 

The pump definitely isn't in an ideal position - it's probably the coldest part of the whole curtilage - but it's in.

Edited September 8, 2022 by Nick Thomas
cut-off mid-sentence; further clarify location with words

[JamesPa]

On 08/09/2022 at 20:06, Nick Thomas said:

The heat pump is butted up right against the house (under the kitchen window

That's interesting, can it be heard inside when to he windows are closed?

[Nick Thomas]

Not with the windows closed, no. If the window or door is open, sure, it's there as a background hum - I stopped noticing it quickly though.

[Nickfromwales]

Fitted a Panasonic in a front garden, detached house but neighbours 1m away one side, no gap the other. The client and their neighbour have been stood next to the unit having a reasonably quiet conversation and the neighbour failed to remark on the unit, even though it was heating the house at the time. Apart from a little additional noise every start-up, the unit is VERY quiet indeed. The only time you’ll hear it, is when you’re trying to hear it, other than that it will disappear into insignificance in no time at all. 
Would be considerate to not time it to come on at night, in the summer, to heat hot water. 

We planned some living ‘acoustic barriers’ to surround it on 2 sides, aimed at deflection and to counteract the surfaces I worried would offer reflection, but seriously not needed other than for aesthetic reasons. 

[PhilT]

The latest leading brands/models are all very quiet at ambient temps above 3degC but below that sound levels start to rise from a whisper to a "roar", however you can barely hear it inside the house, and neighbours are indoors during the very cold periods anyway. The friend who recommended my ASHP had his installed just outside the back door of a 200 year old terraced cottage right up against a thin wood side fence. It has been going for over two years and he's had no noise issues with his neighbours

[JamesPa]

I have just received planning consent for my installation of an ASHP and additional solar panels (which do not clear the hurdles for permitted development because (a) I don't plan to use an MCS registered installer and one possible unit I am considering is marginally too big), but my LPA has seen fit to impose a noise constraint which is both technically significantly more onerous, and also significantly more onerous to demonstrate, than the MCS 020 noise standard applied to heat pump installations which qualify for permitted development.

 

I suspect its ignorance or laziness (notwithstanding that I drew attention to the MCS spec in my application) rather than being imposed for some specific reason; there were no neighbour objections and nothing in an officers report indicating a specific reason of the condition.

 

Has anyone else experienced anything similar or have any comments.  I'm minded to appeal the condition (because I don't think its achievable and its going to cost a fortune to determine anyway), but appeals are currently taking 30+ weeks!

 

The specific condition  is

 

"The rating level of noise emitted from the air source heat pump (ASHP) system hereby approved shall not exceed 10dB below the existing background noise level as measured or calculated at 1 metre from the façade of the nearest noise sensitive property. The measurement and assessment shall be made according to BS 4142:2014+A1:2019 'Methods for rating and assessing industrial and commercial sound' at the nearest and / or most affected noise sensitive premises, with the ASHP system operating at maximum capacity and be inclusive of any penalty for tonal, impulsive or other distinctive acoustic characteristics

Edited December 29, 2022 by JamesPa

[Alan Ambrose]

A bit nonsense that the BSI standard is so expensive, but funnily enough it's available on the Warrington district's site for free:

 

https://www.warrington.gov.uk/sites/default/files/2020-08/cf54_bs_4142_2014_a1_2019.pdf 

 

All that mumbo jumbo (somebody has really gone to town) means essentially measure the background noise level and then with the heat pump running. Obviously the heat pump can't add too much, otherwise it's 'officially annoying'.

 

Essentially you're just measuring how much the sound level increases when you turn your heat pump on. Not sure you really need some consultants for that - it would be good if you can just use a cheap sound meter or even a phone app. Maybe if you can provide a graph like in the BSI doc then you'll be good.

[Temp]

2 hours ago, JamesPa said:

The specific condition  is

 

"The rating level of noise emitted from the air source heat pump (ASHP) system hereby approved shall not exceed 10dB below the existing background noise level as measured or calculated at 1 metre from the façade of the nearest noise sensitive property. 

 

My son is studying acoustics and is on his industrial placement year. He tells me this 10dB below background is more common in London and other cities where background noise levels are higher than the 40dB assumed for the MCS calculation. This could be easier to meet if background noise levels are indeed higher.

 

Edit: I think you will need to measure background noise levels. Perhaps try a mobile phone app first. Depending on how marginal it is then perhaps rent or buy a sound level meter to do a more accurate check. Cheap and nasty ones on Amazon are £20 but only accurate to +/- 3.5dB. TLC have one at <£50  which is +/- 1.5db. HSS website says they have them to rent. This would give you an idea if its remotely possible to meet the condition. If its really marginal you will need to employ a consultant because its critical to your planning permission. That condition could be enforced if a neighbour complains a some point after construction.

 

 

Edited December 29, 2022 by Temp

[Alan Ambrose]

Nice, useful when your offspring have skills . Maybe you could ask him what the standard means in terms of limit in dB over background? 

[Temp]

35 minutes ago, Alan Ambrose said:

Nice, useful when your offspring have skills . Maybe you could ask him what the standard means in terms of limit in dB over background? 

 

The MCS says you must assume background is 40dB at the assessment point and that your ASHP mustn't increase that to more than 42dB. However because of the way you add dB that means the heat pump can't be more 40dB minus 2 or 3db. Eg it must be below background. Say 37.5dB at the assessment point.

 

Following the MCS calculation process it would go something like..

 

Step 8: 40-37.5=2.5dB

Step 9: Look up 2.5dB in the table 7 on page 22 and it says you need to add 2dB to the background. 40+2=42dB

Step 10: Compare the result (42dB) with the limit of 42dB. Its just OK.

Therefore 37.5dB is just OK.

 

I might be a dB or so out as I haven't checked how you are meant to round up/down in Step 9.

 

Edited December 29, 2022 by Temp

[JamesPa]

We live in a quiet road so the background is around 35dBA max.  10 dB below this is unachievable.  Essentially the requirement as specified by the LPA is (I suspect unwittingly) a refusal dressed up as a consent.

 

MCS (ie permitted development) is effectively (close to) 2-3dB below an assumed background of 40dB.  The MCS standard is, unlike the condition specified by my LPA, both deterministic and achievable.

Edited December 29, 2022 by JamesPa

[Temp]

3 minutes ago, JamesPa said:

We live in a quiet road so the background is around 35dBA max.  10 dB below this is unachievable.  Essentially the requirement is (I suspect unwittingly) a refusal dressed up as a consent.

 

MCS (ie permitted development) is effectively (close to) 2dB below an assumed background of 40dB.

 

In which case I think you will have to appeal the condition.

 

I think I would argue that its unreasonable because existing properties are only subject to the 42dB Permitted Development limit in MCS020 where as you are required to meet an unachievable 25dB.  

 

Perhaps also point out it means its unlikely that heat pumps could be installed on any new property in large areas of the district contrary to... and cite any low carbon neutral policies they have. 

 

Do the sums for a gas or oil boiler. Could they meet the 25dB condition? 

 

Can you find any recent developments that have installed heat pumps without this condition?

 

Expect them to argue 10dB under is a common planning condition. Google found this from one Authority.

 

https://www.google.com/url?sa=t&source=web&rct=j&url=https://images.reading.gov.uk/2019/12/EC024_Note_on_EN17_Noise_Requirements.pdf&ved=2ahUKEwj1_Prv0Z_8AhXagVwKHS06C14QFnoECBEQAQ&usg=AOvVaw2BS5fHNtPmmQBiZ5g54u1k

 

Probably worth considering a planning consultant that has noise experience? 

[Temp]

https://www.drplumbingandheating.co.uk/how-noisy-is-an-oil-boiler/

 

Quote

The declared sound level for Worcester Bosch Heatslave domestic oil boilers is 53dB.

 

To get below 25dB with a Q of 4 (Ground and a wall like most oil boilers are installed) the assessment point would have to be around 15 meters away.

Edited December 29, 2022 by Temp

[JamesPa]

53 minutes ago, Temp said:

Do the sums for a gas or oil boiler. Could they meet the 25dB condition? 

That's an interesting one.  However gas and oil boilers are generally installed indoors so don't affect the neighbours.  They certainly couldn't meet the condition if installed outside.

 

My LPA wants the ashp to be so quiet that the neighbours couldn't hear it if they are outside the property.  Thats unrealistic, when it's on full they will be inside sheltering from the cold, or in the swimming pool making a loud noise if I use it for cooling in summer (not currently planned but of course possible).

 

It's a retrofit so, in extremis, I could go for meeting the conditions for deemed consent, but then I have to pay the MCS premium and (ironically) install the louder and uglier of the two alternative units I am considering.

 

 

[JamesPa]

2 hours ago, Alan Ambrose said:

A bit nonsense that the BSI standard is so expensive, but funnily enough it's available on the Warrington district's site for free:

 

https://www.warrington.gov.uk/sites/default/files/2020-08/cf54_bs_4142_2014_a1_2019.pdf 

Thanks for that, breach of copyright by WDC surely, but a saving of £298!

[JohnMo]

Unless you are a commercial or industrial application, then the BS standard it not applicable to a domestic situation.

 

It clearly states

'Scope

1.1 This British Standard describes methods for rating and assessing sound of an industrial and/or

commercial nature, which includes:

a) sound from industrial and manufacturing processes;

b) sound from fixed installations which comprise mechanical and electrical plant and equipment;

c) sound from the loading and unloading of goods and materials at industrial and/or commercial

premises; and

d) sound from mobile plant and vehicles that is an intrinsic part of the overall sound emanating

from premises or processes, such as that from fork-lift trucks, or that from train or ship

movements on or around an industrial and/or commercial site.'

 

I would revert to the council, and ask them to define the correct standard to use, as that one is not appropriate to a domestic situation.  And also state that MCS-020 is the appropriate standard, copy the wording directly from the introduction.

MCS-020.pdf

[ReedRichards]

58 minutes ago, JamesPa said:

... gas and oil boilers are generally installed indoors so don't affect the neighbours.  T

 

 

But the exhaust vents to the outside and it is the exhaust that makes the most noise.  I had an external oil boiler before I replaced it with a heat pump and my next-door neighbour still has one, although it's inside a little brick-built boiler house.   

[HughF]

I’d have just gone ahead and installed whatever you wanted…. And wouldn’t have bothered with the planning part.

 

Just say it’s an air conditioner if asked. Gets around the planning and dno connect & notify rules.

[billt]

An interesting idea, but I suspect that it's not right, after all an air conditioning unit is a heat pump and the rules for air conditioners seem to be the same as for heat pumps, unsurprisingly. I doubt that you'd get very far using that as a defence.

 

I'd probably just have done it as well.