BS 4142 is the British Standard used to assess the impact of industrial and commercial noise on nearby sensitive premises. It works by comparing the rating level of a specific noise source (adjusted for acoustic character) against the prevailing background noise level at the nearest receptor. A difference of around +10 dB or more indicates a likely significant adverse impact. Around +5 dB indicates a likely adverse impact. At or below background indicates negligible impact. Most local planning authorities require a BS4142 assessment when new commercial or industrial premises are proposed near residential properties, or when fixed plant and equipment is being installed. The 2019 amendment (BS4142:2014+A1:2019) introduced important updates to methodology that all current assessments must reflect.
HMO’s and Sound Testing for Part E of the Building Regulations
What is a House in Multiple Occupation (HMO)?
Does Part E of the building regs apply?
Whether Part E of the Building Regulations applies depends on whether the HMO is defined as rooms for residential purposes. The building regulations Part E states;
Interpretation (Regulation 2) ‘room for residential purposes’ means a room, or suite of rooms, which is not a dwelling house or a flat and which is used by one or more persons to live and sleep and includes a room in a hostel, an hotel, a boarding house, a hall of residence or a residential home, but does no include a room in a hospital or other similar establishment, used for patient accommodation.
When rooms are defined as rooms for residential purposes the requirement E1 of Part E of the building regulations applies.
E1. Dwelling-houses, flats and rooms for residential purposes shall be designed and constructed in such a way that they provide reasonable resistance to sound from other parts of the same building and from adjoining buildings.
What do the Department for Communities and Local Government (DCLG) say?
The following extract is taken from the DCLG frequently asked questions
Should rooms in Houses in Multiple Occupation (HMO) be treated as Rooms for Residential Purposes?
There is no single answer to this question. The term “House in Multiple Occupation” (HMO) is defined in the Housing Act 2004, and a wide range of premises will fall within the definition. Many of these premises will contain rooms that would also meet the definition of a room for residential purposes given in regulation 2(1) of the Building Regulations; however there are others that will not. Each case should therefore be considered on its own merits.
When deciding whether a room or a suite or rooms is a room for residential purposes, the list of establishments in which rooms for residential purposes may be found, which is given in the definition in regulation 2(1), provides useful guidance. It states that a room or suite of rooms, used by one or more persons to live and sleep, in a hostel, hotel, boarding house, hall of residence or residential home is included in the definition of room for residential purposes. Consequently rooms or suites of rooms used by one or more persons to live and sleep in HMOs used for those purposes, or in HMOs which have a substantially similar use, are likely to be rooms for residential purposes, although it is necessary to carefully consider each case individually.
Rooms or suites of rooms in HMOs which are not hotels, hostels, boarding houses, halls of residence, residential homes or similar are therefore unlikely to be rooms for residential purposes as defined in the Building Regulations. It is not possible to give definitive guidance, but it is unlikely for example that bedrooms in a HMO which consists of a single family dwelling-house which is shared by a small group of students could be regarded as rooms for residential purposes.
So as you can see there is a degree of ambiguity in how HMO’s and Sound Testing should be approached!
What we have experienced?
We have worked on numerous projects with HMO’s and the level of service dictated by the Building Control Officer requested has varied quite dramatically. We have been requested to provide the following level of services in order to sign the development off:
- Sound Insulation Design Advice only; We have bee instructed to simply provide sound insulation design advice by the Building Inspector in order to ensure the developer is undertaking best practical means to achieve the minimum requirements of Part E of the building regulations. But no sound testing was requested on completion.
- Limited Scope of Testing; In some instance the Building Inspector has defined ‘High Risk’ areas that require acoustically design and testing to achieve Part of the building regulations. These are typically separating walls and floors between communal areas such as Living Rooms/Kitchens to Bedrooms.
- Full Sound Testing: In most instances we are asked to design and sound test all separating walls and floors in accordance with Part E of the building regulations. l
- No Testing; On some occasions Part E of the building regulations has been disregarded entirely.
What we would advise?
In all instances the correct approach is to ensure all party walls and floors are designed and tested to achieve the requirements of Part E of the building regulations. Whilst the cost of the development will increase, the benefit of improved sound insulation in HMO’s will pay dividends in the long term through tenants having a more amenable environment to live in and thus they will be more likely to stay in the HMO longer.
As we have found multiple different approaches to HMO’s and Sound Testing it is imperative to consult your Building Inspector early to ensure you are achieving the standards that they require and don’t have a sound test requested at the end of a project when the acoustic measured have not been included in the design.
How can we help?
We listen to our clients’ needs and present them with practical, cost-effective solutions. This means that we offer a truly bespoke acoustic consultancy service for prices that are considered among the most competitive in the industry. NOVA Acoustics Ltd have a published a huge amount of Free Sound Insulation Design Advice here, including soundproofing floor and wall systems, as well as how to approach acoustic detailing and flanking sound. Click through to our Sound Insulation Design Advice section. Or if you need Sound Testing or Consultancy, give us a call to chat with one of our friendly consultants.
Related article: Pre Completion Sound Testing Explained
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