The following are key terms used in this document:
Air permeability is the physical property used to measure airtightness of the building fabric. It is defined as air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50 N/m²). The envelope area, or measured part of the building, is the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.
The limiting air permeability is the worst allowable air permeability.
The design air permeability is the target value set at the design stage, and must always be no worse than the limiting value.
The assessed air permeability is the value used in establishing the BER, and is based on a specific measurement of the building concerned.
BCB means building control body: a local authority or an approved inspector.
BER is the Building CO2 Emission Rate expressed as kgCO2/(m².year).
Commissioning means the advancement of a fixed building service following installation, replacement or alteration of the whole or part of the system, from the state of static completion to working order by testing and adjusting as necessary to ensure that the system as a whole uses no more fuel and power than is reasonable in the circumstances, without prejudice to the need to comply with health and safety requirements. For each system commissioning includes setting-to-work, regulation (that is testing and adjusting repetitively) to achieve the specified performance, the calibration, setting up and testing of the associated automatic control systems, and recording of the system settings and the performance test results that have been accepted as satisfactory.
Controlled service or fitting means a service or fitting in relation to which Part G (sanitation, hot water safety and water efficiency), H (drainage and waste disposal), J (combustion appliances and fuel storage systems), L (conservation of fuel and power) or P (electrical safety) of Schedule 1 to the Building Regulations imposes a requirement.
Display window means an area of glazing, including glazed doors, intended for the display of products or services on offer within the building, positioned:
a. at the external perimeter of the building; and
b. at an access level; and
c. immediately adjacent to a pedestrian thoroughfare.
There should be no permanent workspace within one glazing height of the perimeter. Glazing more than 3 m above such an access level should not be considered part of a display window except:
a. where the products on display require a greater height of glazing;
b. in cases where building work involving changes to the façade and glazing requiring planning consent, where planners require a greater height of glazing, e.g. to fit with surrounding buildings or to match the character of the existing façade.
It is expected that display windows will be found in planning Use Classes A1, A2, A3 and D2 as detailed in the table below.
Planning Use Classes
Display lighting means lighting intended to highlight displays of exhibits or merchandise, or lighting used in spaces for public leisure and entertainment such as dance halls, auditoria, conference halls, restaurants and cinemas.
Dwelling includes a dwelling-house and a flat and means a self-contained unit designed to accommodate a single household. Buildings exclusively containing rooms for residential purposes such as nursing homes, student accommodation and similar are not dwellings, and in such cases, this Approved Document L2A applies.
Emergency escape lighting means that part of emergency lighting that provides illumination for the safety of people leaving an area or attempting to terminate a dangerous process before leaving an area.
Energy efficiency requirements means the requirements of regulations 23, 25A, 25B, 26, 26A, 28, 29 and 40 of, and Part L of Schedule 1 to, the Building Regulations.
NOTE: In respect of new buildings other than dwellings, the applicable requirements are those of Part L and regulations 25A and 26.
Energy performance certificate means a certificate which complies with regulation 7A of the Energy Performance of Buildings (England and Wales) Regulations 2012.
Fit-out work means that work needed to complete the partitioning and building services within the external fabric of the building (the shell) to meet the specific needs of incoming occupiers. Fit-out work can be carried out in whole or in parts:
a. in the same project and time frame as the construction of the building shell; or
b. at some time after the shell has been completed.
Fixed building services means any part of, or any controls associated with-
(a) fixed internal or external lighting systems (but not including emergency escape lighting or specialist process lighting);
(b) fixed systems for heating, hot water, air conditioning or mechanical ventilation; or
(c) any combination of systems of the kinds referred to in paragraph (a) or (b).
High-usage entrance door means a door to an entrance primarily for the use of people that is expected to experience large volumes of traffic, and where robustness and/or powered operation is the main performance requirement. To qualify as a high-usage entrance door, the door should be equipped with automatic closers and, except where operational requirements preclude it, be protected by a lobby.
Room for residential purposes means a room, or a 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 not include a room in a hospital, or other similar establishment, used for patient accommodation.
Specialist process lighting means lighting intended to illuminate specialist tasks within a space, rather than the space itself. It could include theatre spotlights, projection equipment, lighting in TV and photographic studios, medical lighting in operating theatres and doctors’ and dentists’ surgeries, illuminated signs, coloured or stroboscopic lighting, and art objects with integral lighting such as sculptures, decorative fountains and chandeliers.
TER is the Target CO2 Emission Rate expressed as kgCO2/(m².year).
Total useful floor area is the total area of all enclosed spaces measured to the internal face of the external walls. In this convention:
a. the area of sloping surfaces such as staircases, galleries, raked auditoria and tiered terraces should be taken as their area on plan; and
b. areas that are not enclosed such as open floors, covered ways and balconies are excluded.
NOTE: This area is the gross floor area as measured in accordance with the guidance issued to surveyors by the Royal Institution of Chartered Surveyors (RICS).
CO2: carbon dioxide
BRUKL: Building Regulations UK Part L
UKAS: The United Kingdom Accreditation Service
HVAC: heating, ventilation and air-conditioning
LZC: low and zero carbon
SFP: specific fan power
SEER: seasonal energy efficiency ratio
SSEER: seasonal system energy efficiency ratio
FF: frame factor
DX: direct exchange