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Accredited details (ACDs)
Accredited details are a set of details addressing linear thermal bridges issued on behalf of the government and are used in SAP calculations. Read More
Air-tightness – Air Permeability
Refers to the level of which uncontrolled ventilation losses have been dealt with in a building. For building regulation purposes it is measured in m3 of ‘gaps’ per m2 of the building envelope. Whilst the worst level of ‘air-tightness’ is 10m3/m2@50pa typical values are between 3 and 6. In Passivhaus (PH) it is measured as air-changes per hour (ACH). To achieve PH air-tightness will normally be no worse than 0.6ACH@50pa. In an average sized dwelling 0.6ACH@50pa is almost the same 0.6m3/m2@50pa.
In both cases the building is subjected to an air pressure test at a pressure of 50pa (pascals). For building regulation purposes testing should be carried out by BINDT registered contractors following ATTMA guidlines.
Requirement A
Building regulation requirement relating to structure
Approved document A: Structural Safety
Government issued guidance to assist achieving compliance with building regulation requirement A.
Area-Weighted U-value method
An alternative to the elemental approach to compliance with ADL1B and ADL2B. The sum of all thermal elements multiplied by their U-values for a proposed extension or alteration must not exceed the sum of all thermal elements multiplied by their U-values for an elementally compliant extension or alteration.
BER
Building Emissions Rate (kg/m2) this is the predicted CO2 emissions rate of the building and is calculated by SAP for dwellings and SBEM for other buildings. Only Building regulation controlled aspects are assessed (heating, lighting and ventilation and not things like TVs and fridges etc).
Breathability
This slightly misleading term refers to the ability of the elements of the building (usually just the walls and roof) to take up and release moisture from the air in the building and or its ability to migrate moisture from the inside to the outside of the element of the building without adversely affecting the materials making up the element.
Contrary to common misconception there is no conflict between air-tightness and breathability.
read more – link to paper by Neil May of NBT
Requirement B
Building regulation requirement relating to Fire Safety
Approved document B : Fire safety
Government issued guidance to assist achieving compliance with building regulation requirements.
BREEAM
British Research Establishment Environmental Assessment Method
C
Carbon
CO2
Carbon Dioxide
CfSH
Code for Sustainable Homes
Cob
A form of wall construction using clay subsoil and straw mix. Read more – link to possibly the nicest cob builders in UK.
Cork
Requirement C
Building regulation requirement relating to contaminants and moisture
Approved document C: Resistance to contaminants and moisture
Government issued guidance to assist achieving compliance with building regulation requirements.
DER
Design Emissions Rate (kg/m2) this is the predicted CO2 emissions rate of the designed building and is calculated by SAP for dwellings and SBEM for other buildings. Only Building regulation controlled aspects are assessed (heating, lighting and ventilation and not things like TVs and fridges etc).
Requirement D
Building regulation requirement relating to the control of toxic substances
Approved document D: Toxic substances
Government issued guidance to assist achieving compliance with building regulation requirements.
Enhanced Construction Details (ECDs)
Similar to ACDs but more thermally robust and issued by the Energy Savings Trust
Read More
Requirement E
Building regulation requirement relating to the resistance of the passage of sound
Approved document E: Resistance to the passage of sound
Government issued guidance to assist achieving compliance with building regulation requirements.
EPS
Expanded Polystyrene
Emissivity
the rate that heat or light radiates
Fixed building service
A building regulations term referring to controlled heating, lighting, ventilation equipment
Fixed building fitting
A building regulations term referring to doors, windows and roof lights or roof windows
Foam Glass
An aerated insulating product made from glass usually with high structural properties.
Requirement F
Building regulation requirement relating to ventilation of buildings
Approved document F: Means of Ventilation
Government issued guidance to assist achieving compliance with building regulation requirements.
Green Wash
A form of spin in which green PR or green marketing is deceptively used to promote the perception that a policy or product is environmentally friendly.
G-value or solar factor
Is the percentage of total solar radiant heat energy transmitted through glazing (the sum of energy transmitted directly and energy absorbed and re-emitted to the interior).
Requirement G
Building regulation requirement relating to Sanitation, hot water safety and water efficiency
Approved document G: Sanitation, hot water safety and water efficiency
Government issued guidance to assist achieving compliance with building regulation requirements.
Requirement H
Building regulation requirement relating to drainage and waste disposal
Approved document H : Drainage and waste disposal
Government issued guidance to assist achieving compliance with building regulation requirements.
Interstitial condensation
is where the moisture from within the building ( suspended in the warm air) condenses within the structure. If not adequately dealt with not only will it reduce the thermal efficiency of the structure it can also lead to the degradation of the materials.
Requirement J
Building regulation requirement relating to combustion appliances and fuel storage systems
Approved document J : combustion appliances and fuel storage systems
Government issued guidance to assist achieving compliance with building regulation requirements.
Requirement K
Building regulation requirement relating to the protection from falling, collision and impact (stairs, ramps and guarding)
Approved document K : protection from falling, collision and impact
Government issued guidance to assist achieving compliance with building regulation requirements.
Linear thermal bridges
This is the additional heat loss through the fabric of a building and junctions of thermal elements e.g. where a wall meets a floor. see also y-value
Requirement L
Building regulation requirement relating to the conservation of fuel and power
Approved document L: the conservation of fuel and power
Government issued guidance to assist achieving compliance with building regulation requirements.
Living Roofs
Living roofs are roofs that encorporate planting. Green roofs are a type of living roof and are split into two main types: Extensive and Intensive.
Extensive green roofs have shallow soil and therefore shallow rooting plants whereas Intensive green roofs have deep soil layers and can accommodate deeper rooting plants and shrubs. Brown roofs are living roofs which rather than having a soil layer have hardcore and or stones, very minimal soil content and are left to self seed. The benefit of living roofs is the addition of a natural habitat, a slowing down of rain water and some thermal buffering.
For more information click here or here.
MVHR – Mechanical Ventilation with Heat Recovery
A whole house mechanical ventilation (extract and supply) system which dramatically reduces heat loss associated with ventilation. These systems are essential in Passivhaus, and for houses to comply with both requirement F and L where air-tightness is 3m3/m2 or tighter.
Requirement M
Building regulation requirement relating to access to and use of buildings
Approved document M: access to and use of buildings
Government issued guidance to assist achieving compliance with building regulation requirements.
NHER
Software that produces SAP and NHER ratings – see also SAP
Noble Gases
Gases which don’t mix with other gases – Argon, Helium, Krypton, Neon, Radon and Xenon. Argon, krypton and Xenon can be used to fill cavity in double and triple glazing units to improve efficiency.
Requirement N
Building regulation requirement relating to safety of glazing
Approved document N : glazing – safety in relation to impact, opening and cleaning
Government issued guidance to assist achieving compliance with building regulation requirements.
Paint
read more – link to paper on eco paint by Neil May of NBT
Passivhaus
Passivhaus is a standard and methodology for the design and construction of highly energy efficient buildings that do not require traditional heating or cooling services.
Requirement P
Building regulation requirement relating to electrical safety in dwellings
Approved document P : electrical safety
Government issued guidance to assist achieving compliance with building regulation requirement.
Rammed earth
A building technique where walls are constructed from earth. The earth is compressed by manual or mechanical means. See http://www.rammed-earth.info/ for the UK experts on the subject.
Regulation 7 : Materials and workmanship
Government issued guidance to assist achieving compliance with building regulation requirements.
SAP – Standard Assessment Procedure
Whole house (Dwellings) energy and carbon dioxide emissions estimating tool used to demonstrate compliance with building regulations.
SBEM - Simplified Building Energy Model
Whole building (buildings other than Dwellings) energy and carbon emissions estimating tool used to demonstrate compliance with building regulations.
TER Target Emissions Rate
The target rate of CO2 emissions which new buildings must not exceed as stated by the building regulations. For dwellings the TER is set by SAP for other buildings it is set by SBEM. The target is based on the proposed building designed to a base set of values for envelope and services efficiencies and therefore is a movable target.
Thermal element
A building regulations term relating to a controlled floor, wall, or roof that separates a conditioned (heated or cooled) space from an unconditioned space (unheated or not cooled or outside) or differently conditioned space (e.g. one side heated the other cooled)
U-value
The U-value or the overall heat transfer coefficient, describes how well a building element conducts heat. It is a measure of the rate of heat transfer through a building element over a given area, under standardised conditions.
Vapour Resistance / Resistivity
The way that materials/components making up your walls,floors and roofs deal with the flow of moisture vapour is crucial to the longevity of the components and the thermal performance of those building elements. If moisture gets into, for example, a wall and cannot get out eventually the structure can get saturated and may rot. As moisture builds up the thermal performance (its ability to resist the passage of heat) drops which in turn can encourage more moisture to condense within the structure and therefore setting a negative feedback loop (vicious circle).
There are numerous measures relating to this Diffusion Resistance Factor, Sd Value, Moisture Resistance Factor, Vapour Resistivity, Vapour Resistance, Vapour Permeability, y (mu) value or factor.
For guidance in converting between different moisture/vapour factors see guidance from BuildDesk (U value software).
For a little more techie explanation of the different terms the glossary at Natural Building Technologies website is useful.
For a very techie explanation of the different terms the WUFI website is useful.
XPS Extruded Polystyrene
(see also EPS Expanded Polystyrene)
y-value
also known as psi-value. A symbol or term to express linear thermal bridging
Zero Carbon
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