Questions and answers on Building Regulations

Part B – Fire Safety

Now that BS9999 has replaced the BS5588 series of standards, which standard should I now use?

When an Approved Document makes reference to a named standard (listed in the appendix of the Approved Document), this is the relevant document to use. However, if this version of the standard has been revised or updated by the issuing standards body, the new version may be used as a source of guidance provided it continues to address the relevant requirements of the Regulations.

Volume 2 of Approved Document B currently refers to the guidance in several of the BS5588 series of standards as a means of showing compliance with the requirements of Part B (Fire safety) of Schedule 1 to the Building Regulations. Until such time as the Approved Document is amended, these references remain part of the guidance approved under section 6 of the 1984 Building Act. As such, compliance with the guidance referred to would confer a legal presumption of conformity with the relevant requirements of Part B. Following any other guidance would not confer that legal presumption.

Where designers choose to follow the relevant guidance in BS9999 they will need to satisfy themselves and the relevant authorities that this guidance adequately addresses the requirements of Part B. It is strongly recommended in such cases that designers discuss their proposals with NHBC before starting work.

Are alternative escape windows required at any level in a three or four storey house?

No. This may differ, however, if the house has inner rooms.

What are the considerations for metal framed suspended ceilings in protected entrance halls to flats?

If the metal framed suspended ceilings are erected and lined with plasterboard prior to the construction of the internal partitions, consideration would need to be given to the prevention of the fire spreading within the void and over the partitions enclosing the protected entrance halls.

The installation of 30 minutes cavity barriers positioned vertically in line with partitions surrounding the protected entrance halls. Or a 30 minute horizontal cavity barrier installed throughout the whole of the flat compartment. Considerations should be given to the recessed lights that are fitted with hoods and extract duct penetrations should be suitably fire dampened.

What do I need to consider when designing mechanical ventilation to basement car parks?

The three traditional approaches to providing ventilation to car parks, taken from Approved Document B - Fire Safety, are:

• Open sided (where there are no basement storeys and high levels of natural ventilation can be achieved) - Each storey should be naturally ventilated by permanent openings equal to 1/20th (5%) of the floor area, half of which is arranged equally on opposing walls.
  
  
• Natural Ventilation - Where car parks that are not deemed to be considered 'open sided' are provided with more limited natural ventilation, permanent openings equivalent to 1/40th (2.5%) of the floor area are required, of which at least half (1/80th) should be arranged equally on opposing walls to achieve cross ventilation. Smoke vents at ceiling level may be used as an alternative to permanent openings in the perimeter walls however their distribution and equivalent ventilation area must be arranged to provide a through draught.
  
  
• Mechanical Ventilation - Must be designed to run at a minimum 6 air changes per hour, increasing to 10 air changes per hour in the event of a fire, with an even distribution of high and low level extract points. It must also be provided with an independent power supply, designed to operate in event of failure of the main power supply. It should be designed to run in two parts, each capable of extracting 50% of the design extract rate. Have extract fans rated to run at 300 degrees centigrade for a minimum 60 minutes, combined with ductwork and fixings constructed of materials with a melting point not less than 800 degrees centigrade and ensure that the smoke discharge points are sited so as to avoid any risk from smoke being recalculated into building or affecting means of escape. Modern alternatives can also be considered (SHEVS).

Are the European classes for surface spread of flame ratings equivalent to the British classes?

The first point to make is that there are no direct equivalences between the Euro classes and the British classes. The reason for this is simply that the British and European tests measure different things. That does not make them necessarily a better or worse material.

Use the following table as a guide:

• A1 for Non Combustible
• A2 for Limited Combustibility
• B for Class 0
• C for Class 1
• D for Class 3
• E for Class 4
• F for No performance determined

The above is only a guide and it really depends on the material. To get a European classification you have to do a European test and for a British classification, a British test.

I am undertaking shop fitting work and there are existing unprotected steel beams in the ceiling void. Do I need to add fire protection?

If there is no change of use or structural alteration and the situation regarding fire protection is no worse than it was before, then building regulations do not apply here as they are not generally applied retrospectively. Therefore Building Control should not require you to upgrade the fire resistance to the beams.

However if the building is a workplace the client or tenant must carry out a Fire Risk Assessment and this should include structural fire protection issues if visibly found to be defective and where reasonably easy to improve matters. In this case therefore the client/ tenant should include for 1 hour fire resistance to be added (for buildings up to 18m in height).

I have an old fire certificate for my offices and have heard they are no longer needed, is this correct?

Fire Certificates are no longer required for workplaces as theFire Precautions Act 1971legislation has been withdrawn. The current legislation is the Regulatory Reform (Fire Safety) Order 2005,sometimes called theFire Safety Order or RRO, which came into force in October 2006.

This requires that a Fire Risk Assessment is carried out for all workplaces and where there are more than five employees this must be a written assessment.

In addition the legislation also applies to the common parts of blocks of flats for the first time. The person occupying the premises should carry out the risk assessment, or employ a competent person to do so. For complex or multi-occupied buildings a landlord may have to provide a complementary risk assessment for common parts.

Read our detailed guidance in Standards Extra 38.

What fire precautions should my specification allow for when carrying out a refit of a shop unit?

Assuming that the property was a shop prior to carrying out the works, for Building Regulation purposes the works fall under the category of 'material alteration'. As such,the fire precaution measures to the existing parts of the development should be as good after the works as they were before, and any newly constructed or modified areas should meet the current recommendations of Approved Document B. However, the premises also fall under the requirements of the Regulatory Reform (Fire Safety) Order 2005 and under this legislation, a suitable fire risk assessment and evacuation strategy must also be carried out and managed by a competent person. Whilst not always the case, it is generally accepted that the works necessary to satisfy both sets of legislation will include the following:

• Upgrading or replacement of fire alarm to meet BS5839 Part 1
• Upgrading or replacement of emergency lighting system to meet BS5266 Part 1
• Servicing of fire doors to ensure that they are self-closing, are fitted with adequate smoke seals (where necessary) and that any in tumescent strips are intact
• 'Fire Exit' signage is in the correct positions and clearly visible
• Ceiling linings and any storage cupboards (particularly under staircases) are suitably lined with fire-resisting construction

For dwellinghouses, where is the 45m hose distance for fire brigade access measured?

From a turning circle position or site entrance a further 20m driveway distance is permissible, from which point the 45m hose distance is measured. If the driveway continues beyond 20m from turning circle position or site entrance, then the turning circle should be moved to a maximum of 20m from the end of the driveway.

For a block of flats fitted with a dry (or wet) riser, how close should the fire service tender be able to get to the entrance of the building?

A fire service appliance should be able to park within 18m of a dry (or wet) riser inlet, and be able to clearly see the inlet position.

Are fire alarms or detection systems required to common parts of blocks of flats?

Requirement B1 requires 'appropriate provisions for early warning of fire'. Due to the high degree of compartmentation in residential developments the fire safety approach in Part B assumes only the occupants of the flat where the fire starts will initially evacuate. The occupants of other flats will remain in place and will only evacuate if the fire brigade consider it necessary after their arrival. There is therefore no need for an alarm system to notify all residents of a fire and there is generally no need for a fire detection system in the common areas of blocks of flats.

There may however be a need for detection in common areas to activate fire protection systems, such as automatic opening vents and fire doors on hold open devices, but these detectors should not be connected to alarm sounders.

Communal alarm systems may be appropriate where the building contains sheltered housing and centralised management controls are in place.

When would a large hallway in a dwelling house be considered a habitable room for the purposes of Part B?

The following factors can be considered when deciding if a hallway is a habitable room:

1. Hall size - is there potential for the space to provide living / habitable accommodation, eg. dining table, lounge chairs etc.?
2. Are there other rooms available for the range of living purposes, ( ie. lounge, dining room, study?). Similarly, what type of accommodation is appropriate for the dwelling.
3. The arrangement of doors giving access to other rooms / spaces / open air may mean that whatever its size, the hall cannot be reasonably be used for any other purpose.
4. The proportion of the rooms and hall in relation to the overall size of the dwelling.

When does a storage space in a loft become a habitable room and require appropriate means of escape provisions?

The provision of a storage space within the loft area is acceptable, however the provision of an additional floor level, to be potentially used as habitable accommodation should not be considered without providing adequate means of escape. The following factors should be considered when assessing a storage space:

1. Have the ceiling joists or attic trusses been provided
2. Have windows or veluxes been provided for light and ventilation
3. The size of the loft access hatch
4. The ventilation provision to the roof space
5. Whether power outlets have been provided in the roof space
6. Whether plasterboarding has been provided to form an enclosure

Definitive guidelines cannot be provided, but the important factor is to ensure that if the loft space can be readily and easily adapted to provide habitable accommodation, then further details and assessment will be required.

Can I provide a step to an alternative escape window if the installed window has a cill height more than 1100mm above the finished floor level?

A step proposed as a remedial solution should only be considered if it can be reasonably considered to be part of the permanent structure of the floor. This would be a matter of judgement in each case but an isolated step on a plain wall adjacent a window is unlikely to be acceptable.

Where escape windows are installed with the bottom of the opening greater than 1100mm above floor level, the provision of a protected escape route would be acceptable.

Can I use thermoplastic insulation materials in a warm roof deck which passes over a compartment wall?

No, thermoplastic insulation materials should not be used in this situation, as referenced in Diagram 11 and Diagram 30 of Approved Document B:2006 Vol. 2. The reason for this restriction is that thermoplastic insulation materials have a tendency to melt and the resulting voids can provide a route for fire spread over or through the line of compartmentation.

Thermo-set insultation, such as Polyurethane (PUR), Polyisocyanurate (PIR) and Phenolic foam, whilst technically classed as combustible, is acceptable as they tend to exhibit charring behaviour when exposed to fire, and so are acceptable and permitted to cross the line of compartmentation.

Providing the roof covering can achieve the external fire rating of AA, AB or AC, thermo-set insulation products are acceptable with adequate fire stopping to ensure the potential for fire spread over or around the insulation is restricted.

Should refuges for the disabled be provided in residential basement car parks?

Refuges for disabled people are not required in car parks (basement or otherwise) serving residential premises. If the car park was open to members of the public and serves other non-residential uses, then this principle may change, and the guidance of BS5588-8 and BS9999 should be considered.

Is there an alternative to providing sprinklers in residential buildings above 30m in height?

There is a lot of supporting information to consider any alternative, although it would be difficult to prove an acceptable alternative solution.

Increasing fire resistance of compartmentation could be considered, but sprinklers are also beneficial to life safety and fire fighting provisions, so whilst an increase in compartmentation will contain the fire within a specific area it will not control the fire temperature. Without sprinklers containment may be compromised.

A fully fire engineered design may be able to present an alternative solution, but it would be difficult to prove compliance with Building Regulations.

Part C – Site preparation and resistance to contaminants and moisture

Why do we need to check for radon?

This is a requirement under Approved Document Part C Building Regulations. The Regulations provides an obligation to inform builders at the earliest stage if Radon is found on a site as this may affect the ability to achieve mortgages on properties.

Is a radon sump required where the radon barrier is installed below a ventilated air space beneath a suspended concrete floor?

Depressurisation/ventilation should be provided below the level of the radon barrier. Where the radon barrier is installed below the ventilation air space under a suspended concrete floor, a radon sump will be needed below the radon barrier to provide provision for this (see below).

Part D – Toxic substances

Questions will be posted here shortly

Part E – Resistance to the passage of sound

To satisfy Requirement E3 (Reverberation in the common internal parts of buildings containing flats or rooms for residential purposes), is it necessary to treat all the common parts?

The purpose of this Requirement is to protect residents from noise produced in reverberant common areas. The Requirement only applies to "corridors, stairwells, hallways, and entrance halls which give access to the flat or room for residential purposes". To comply with this, it is recommended that absorbent treatment should normally be applied only to common areas onto which dwellings open directly.

Where separating walls, without doors or windows, are adjacent to common areas it would not normally be necessary to treat the common areas, assuming normal usage. Other situations are dealt with in paragraph 0.8 of Approved Document E (2003).

This means that reverberation measures (e.g. acoustic ceiling tiles) are only required in areas that lead directly to flat entrance doors e.g. common corridors/lobbies and not staircases in most flats,BUT reverberation measures in the staircase where the flats are accessed directly from the stair, such as small single stair flats.

What are my options to meet sound insulation requirements?

Pre-completion testing or Robust Details.

For pre-completion testing, the solution would include:

• Follow the design guidance in Approved Document E
• Set an appropriate testing regime
• Ensure masonry walls are wet plastered
• Ensure joints are fully filled with mortar
• Ensure wall ties are specified correctly
• Ensure cavities are clean and continuous
• If using beam and block floors, ensure you obtain specialist design advice
• Ensure suspended ceilings are provided below concrete plank floors, and
• Remember the builder takes responsibility should a sound test fail

Robust Details approach:

• Register the design with Robust Details Limited. Contact www.robustdetails.com or 0870 2408209
• Ensure construction is strictly to the robust detail design

Part F – Ventilation

What are the main changes included in Part F 2010?

Read our guidance note here

What is the security risk of openable windows?

The guidance within the Building Regulations is that all toilets and cloakrooms should be provided with 6 litres / second of purge ventilation. Under Table 1.2a of Approved Document F1, the ventilation can be provided by purge ventilation with an opening window equal to 1/20th of the floor area. This would only be acceptable where security is not a risk. It is assumed that security is only a risk where the window serves a toilet or cloakroom on a level that is accessible from the outside

Part G – Hygiene

If the required 125 litres per day per head is achieved by limiting the water supply, is a grey water system still required to achieve compliance with the new Part G?

No. The requirement is that you achieve the mains water supply is providing no more than 125 litres per day per head. However, the inclusion of a grey water system could be used to offset the 125 litres / day / person requirement.

Part H – Drainage and waste disposal

Questions will be posted here shortly

Part J – Combustion appliances and fuel storage systems

What are the main changes included in Part J 2010?

Read our guidance note here

Part K – Protection from falling, collision and impact

What types of guarding design are acceptable to comply with Part K?

See Guidance Note

What is the minimum guarding height to balconies?

Measured from the balcony floor level, the minimum requirement is 1100mm.

Should guarding be provided where parapets up to 300mm above the finished floor level are provided?

Yes, an 800mm guard height should be maintained above a parapet, and the design should not be climbable.

If using wire mesh infill panels to balcony guarding, what design considerations should be adopted to ensure the guarding remains not readily climbable?

The wire mesh should not propose a foothold. Therefore for designs incorporating parallel wires in both directions, a maximum gap of maximum 35mm is required. Please refer to the diagrams below for guidance on different mesh designs.

Part L – Conservation of fuel and power

What are the main changes included in Part L 2010?

Read our guidance note here

When do I need a DER / TER / EPC / SBEM?

You will find this on the NHBC Energy Rating service

Can multi-foil insulation material be used to achieve the thermal performance requirements for a new residential building?

Currently NHBC can accept Thinsulex, or a suitably British Board of Agrement certified product.

Will standard light fittings fitted with low energy light bulbs satisfy the requirements of Part L 2006 and Part L 2010?

In recognition of recent changes to EU regulation, which relates to the phasing out of traditional, inefficient and high energy use light bulbs, the guidance concerning 'internal lighting' in the Domestic Building Services Compliance Guide, which supports Part L 2010, has been amended.  The 2010 guidance now permits either:

• Dedicated fittings that only accept low energy bulbs or;
• Standard fittings (e.g. Edison screw or bayonet mount) supplied with low energy bulbs

Where standard fittings fitted with low energy bulbs are provided, this will satisfy the requirements of Part L 2010. In recognition of the phasing out of traditional high energy light bulbs, the above criteria for internal lighting may also be applied to sites being developed under Part L 2006.

Where low energy bulbs are not being provided, it will be necessary to show compliance by providing low energy fittings which only accept low energy light bulbs.

For all developments, where standard light fittings are used, the low energy bulbs must be installed on site in order for Building Control to be satisfied as to compliance.

Part M – Access to and use of buildings

When is a stepped approach to a new dwelling acceptable?

Where the gradient exceeds 1 in 15, or where there are planning constraints, steps can be considered. Steps must be designed to meet the needs of disabled people. There should be a clear landing of 900mm at the top and bottom of the stair, a suitable handrail should be provided to one side of the steps where the flight comprises three or more risers, and step profiles should be designed to avoid tripping hazards.

When do I need to provide a lift in a new non-residential building?

In principle, the provision of a lift for multi-level new buildings should be the starting point for any design. However, there are situations where alternative arrangements can be considered to provide 'reasonable provision'. For example:

• The floor area of a new building may mean it would be impractical in terms of available floor space remaining should a lift be provided
• Are the uses on upper floors the same as those on the entrance floor?
• Is the accommodation in a split-level layout?
• How much traffic is expected between floors? Would a chair lift be a suitable alternative?
• Is it acceptable for the upper or lower levels to only be accessible by the able bodied such as storage areas, racking systems and manual handling?
• Is there toilet accommodation planned on the upper floors?

I am replacing a shopfront, do I need to make a building regulations application and does Part M apply?

This work is a 'material alteration' and is controllable by building regulations so an application is required.

Part M will apply in all regards, so door widths, opening forces and a level threshold should be provided to meet Part M unless unreasonable to do so, in which case the access statement could be used to justify departure. Remember the DDA will still apply to buildings where goods or services are provided so this may be a good time to make improvements where reasonable to do so.

You mention the word 'reasonable' a lot in the above, what does this mean?

What is 'reasonable' depends on the merits of each individual case, including the scope and scale of the premises and takes into consideration the amount of building work, financial costs involved, and the benefits in in carrying out an alteration to provide compliance with a particular regulation. Where the building or element may be newly constructed then most work is reasonable, whereas for existing buildings or those which are listed or historic then this may affect what is reasonable.Building Control should use professional skill and judgement, including common sense, when arriving at decisions whilst striving to maximise compliance in line with the regulations.

Part N – Glazing – safety in relation to impact, opening and cleaning

I am replacing full height and length glazing to a unit which is to be converted to a new retail unit- what are the requirements in regard to the type of glass used and any markings or features required in order to make it apparent?

The glazing to be replaced will be such that it is located within a Critical location- those areas being located as

a) between finished floor level and 800mm above that level in internal and external walls and partitions

b) between finished floor level and 1500mm above that level in a door or in a side panel, close to the edge of the door (ie within 300mm of the edge of the door)

The glass to be installed within the above areas should

i) break safely if it breaks( be glass specified to meet British standard 6206: 1981- Specification for impact performance requirements for flat safety glass and safety plastics for use in buildings)

In terms of safe breakage, a glazing material suitable for installation in a critical location would satisfy the requirements of Class C of BS6206 or installed in a door or in a door side panel and has a pane width of 900mm the requirements of Class B of the same standard

ii) Be robust- some glass gain strength through thickness- annealed glass, poly carbonates and glass blocks are inherently strong - Some annealed galls is considered suitable for use in large areas

iii) be permanently protected- if glass , in a critical location is installed behind a permanent screen- the screen should:

prevent a sphere of 75mm from coming into contact with the glazing; be robust and if intended to protect glazing that forms part of protection from falling, be difficult to climb

Note- the glazing in a critical location which is afforded permanent protection, does not itself need to meet the requirements of items i-iii above.

Where glazing is installed in critical locations in which people are moving in or about the building and might not be aware of presence of glazing then suitable marking or manifestation should be provided to the glazed section.

This manifestation should can take the form of various markings on the glass (eg stickers, etching, features) and some examples are- broken or solid lines, patterns and company logos- Permanent manifestation of large areas of glazing is only required when other means of indicating the presence of glazing are NOT used (these other means may include mullions, transoms, door framing or large pull or push handles)

Part P – Electrical safety

When does Part P apply?

To houses and flats-including common parts but not lifts, non residential buildings that share a power source with a dwelling i.e shop with flat over, conversion, extensions and alterations, land associated with a building ie fixed garden lighting, pond pumps, sheds, garage and green houses.

What work does not need to comply with Part P?

When the work is limited to replacement sockets and switches.

I am intending to carry out some electrical work in a bathroom and wiring within a garage and provide new electrical installation to a bedroom.Are there any formal regulations I must conform to and are there any legal requirements for this work and who can carry them out?

The works within the bathroom are within a special  location the new outdoor wiring to the garage is new and the new circuit to the bedroom would under the guidance to meet Part P be classed as notifiable works under the requirements of Part P1 of the Building Regulations 2000 and a formal application to the local authority building control or private approved inspector building control body to carry out these works would be required.

The above works are to be carried out by a competent person or installer:

If that person or installer is registered with a Competent Person Scheme they are qualified to carry out specific types of work in accordance with Building Regulations and will deal with Building control issue with a certificate on completion of the work which can be used as proof for a Home Information Pack (HIP)

If you do not use an installer registered with a Competent Person Scheme then you will have to submit a building notice or full plans application and pay a fee to have Building control body come and inspect the work you have carried out.