Building Environmental Performance Open Dialogue
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  Building Environmental Performance Terminology

Technical terms, definitions and associated parties
In this section of the site you may find technical terms that may appear on regulations, specification documents, planning requirements, research papers, technical drawings regarding sustainable urban design and low carbon buildings.


The portion of radiant heat a material may absorb compared to that of a black body at the same temperature.


The extent to which a material can keep on absorbing heat. This relates to thermal mass.


Measures a surface's diffuse reflectivityby being the ratio of radiation reflected to the incident. Also known as solar reflectance when referring to solar energy.

All weather pathway

Pedestrian path that may be used regardless of weather conditions.

Articulation of street facing façades

Design elements of the street frontage that help create the streetscape environment.


A mineral used for insulation due to its chemical and flame resistance, sound absoption and tensile strength properties.

Baby friendly designation

Designation awarded to hospitals supporting breastfeeding.

Blue space

Spaces containing an aquatic feature e.g. shoreline, lake, reservoir, fountain.


Building information models include detailed information regarding a building's construction stages and what level of progress is to be achieved per each stage, building geometry via 3D drawings, thermal properties of the building shell in detail per each construction element (i.e. windows, walls, floors, ceilings, roofs etc), building services including their location within the 3D models and the type, sizes and performance of the systems involved.

Binding mechanisms

The commitments are confirmed through one or more of the following:

  • For buildings where the end owner is known, a legal commitment /contract /purchase agreement between developer and future owner demonstrates a commitment to achieve a specific level of sustainability performance
  • Where the end user is unknown, a legally binding commitment to deliver the service, facility or amenity should is in place, such as a planning condition, obligation or permit to deliver a specific level of sustainability performance

The Building Research Establishment is a multi-disciplinary, science centre focused on improving buildings and infrastructure, through research and knowledge generation. The BRE develop a range of products, services, standards and qualifications that are applied worldwide to bring about positive change in the built environment.


The Building Research Establishment Domestic Energy Model is the British government's calculation methodology for estimating dwelling running costs regarding space heating, domestic hot water, lighting, appliances and cooking.
The outcomes are based on property size, geometry, number of occupants, fuel type and fabric insulation levels.


The Building Research Establishment Environmental Assessment Method is the first sustainability assessment scheme regarding the built environment, launched in 1990 with over 600,000 certified buildings in 78 countries. It is an international standard adapted locally, operated and applied through a network of scheme operators, assessors and industry professionals. BREEAM is able to show the added value in higher performing buildings and rewards sustainable design across the life cycle of master planning projects, infrastructure in addition to new built and refurbished buildings.

BSRIA Guide 67/2016

This British guide offers a practical approach on life-cycle costing, the construction and operation of buildings through presenting the principals and then assessing alternatives (compatible with ISO 15686) after calculating and fine tuning the costs and interpreting results of the analysis followed through.

Building contract

Written agreement between the client and the contractor regarding the project's design and construction. This contract may include design duties for specialist subies or design team members.

Capital cost

Expenses for the construction of a project. This includes the actual construction with associated preparatory works, equipment, labour and materials but also site management, construction financing, insurance and relevant taxes, inspection and testing. Not included are costs associated with land procurement, clearance, design, statutory approvals and post occupancy care.


Any chemical substance that may cause cancer through DNA mutation or increased cell division.

Cash in lieu of free parking

Incentive payments to building occupants not using a parking space.

Centre based early childhood education

Education based out of any central facility meaning i.e. a school.

Capital cost reporting

This is necessary for sustainability schemes to become able to identify and present cost effective solutions. Thus capital cost information assists research in cost and savings of developing sustainable buildings.

Certificates of construction

Such certificates may include energy performance (EPCs), air permeability, thermal bridging accredited or enhanced construction details (ACDs or ECDs), responsible sourcing of materials (i.e. ISO 14001, BES6001, Forest Stewardship Council), Considerate Constructors (CoC), Environmental product declaration (EPD), environmental management systems (EMAS), renewable energy installation via microgeneration accreditation scheme (MCS).


A machine that generates heat and electricity. Such units may replace boilers and result to financial and environmental benefits.

Chromated copper arsenates - CCA

Wood preservative. It belongs to pesticides collectively recognized as chromated arsenicals. These contain chromium, copper, arsenic that protect wood.

Circadian rhythm

An internal clock in our body that keeps hormones and bodily processes on a 24-hour cycle. Our body includes several such rhythms wherein tissues and organs have their own rhythm, all synched to the master clock within our brain.

Cold bridging

The locations within the building fabric where a highly conductive material passes fully through a particular layer is considered to be bridged.

Cold roof

A roof insulated at ceiling roof leading to the space above acquiring temperatures closer than those of the outdoor environment.

Color rendering index (CRI)

Comparison of how we preserve eight to fourteen colors under a particular light source in comparison to a black body source of the same color temperature.

Communication records

Correspondence (letter, e-mail, meeting minutes, publication) amongst project stakeholders or third parties that may confirm appointment, action or results.

Communication strategy

The way a project team will correspond, agree on project aspects, monitor progress, commit on implementing changes etc which includes protocols regarding information issued between the various parties formally but also at informal exchanges.

Community supported agriculture (CSA)

Program in which individuals support a particular farm via purchase of shares of the production delivered to a convenient drop-off location.

Component level LCC options appraisal

Life cycle costing appraisal for cost planning specification choices of systems or components at project design stage. Such an appraisal requires 'service life planning' meaning a project's local environment and conditions need to be analyzed and their resulting requirements satisfied.
This entails that included within the design are measurements and resulting commitments on:

  • the expected life of a project rather than the contractual design life
  • commitments regarding minimum performance of all project components during design life
  • additional cost due to components repaired or replaced during design life
Concept design

The stage of a design within which outline proposals are developed.
These regard outline specs, the building form, spatial planning, structural and building services strategies, initial cost budgets that influence the design program and the ability to satisfy BREEAM requirements.
The above include a sustainability strategy, operation and maintenance strategy, risk assessment, handover strategy, project program review, construction logistics for efficiency, health and safety strategy, third party consultation, research and development aspects.

Concession stand

Food stand, kiosk that serve at sporting events, theatres, amusement parks, other venues, often contracted out to third parties/vendors.


The process in which heat is transferred through a material without molecules changing position

Considerate construction practices

The following are examples of considerate construction practices that provide possible ways of meeting the criteria for single dwellings. Further examples can be found at the Considerate Contractors Scheme website under Examples of Good Practices.

Keeping the site clean and tidy:

  • Ensure there is no loose materials or debris lying around the site including the perimeter
  • Vehicles are regularly checked for cleanliness
  • Implement a 'Tidy Friday' initiative
Reduce the impacts to the community:
  • Schedule the timing of deliveries to the site to avoid disturbance to local residents
  • Ensure that any noisy work is carried out at agreed times with adjoining neighbours
  • Record car registration numbers of all operatives in the event that a complaint was made with regard to nuisance parking
A drive for continuous improvements in safety:
  • Toolbox talks on safety matters
  • Passport or helmet stickers for operatives who have successfully completed health and safety training
  • Near miss reporting procedure
A commitment to respect and provide fair treatment of all workers:
  • A 'Respect for people' wall chart displayed, recording satisfaction levels with welfare and other relevant topics
  • Questionnaires issued to all operatives to establish what can be done to improve working conditions
  • Information on dealing with abusive behaviour
Provide suitable site facilities:
  • Suitable toilet facilities for male and female operatives
  • Rest areas for operatives to have breaks away from work areas
  • Suitable first aid facilities
Consultation feedback

Comments from stakeholders that influence and maybe lead to alterations of a project's design and/or operation-use and how this has been achieved.

Construction specification

A document describing the building design at considerable detail. Some features may be left to the contractor's judgement based on the actual time of construction, product availability, market prices, provided the particular feature is built in line with the quality and performance required and detailed within this document.

Consumer run or peer programs

Programs owned, administratively controlled, operated by individuals with mental health issues. At least 51% of governance is controlled by such individuals. Programs typically offer mutual support, community building services i.e. peer counseling, linkages to resources) and advocacy.

Construction stage information

Data assembled after each building's component or part is concluded. This will include commissioning records and reports, purchase orders, metering data, log books, formal letters of implementation of a design in line with the specification.

Contractual tree

A diagram clarifying relationships between parties (client, contractors, design team) within a project.


The process in which heat is transferred from one material to another via the movement of particles.

Conventional bicycle lane

Portion of road not buffered from traffic or parked vehicles, ideally demarcated with pavement signage indicating shared use with motorists.

Cool pavement

Pavement that is coated with materials that reflect solar energy or enhance evaporation maintaining temperatures low.

Cool roof technology

Roof that is coated with materials that reflect solar energy maintaining temperatures low. This is possible via use of reflective paint, sheet covering or reflective tiles or shingles.

Correlated color temperature (CCT)

Color temperature at which a blackbody could produce a spectral distribution similar to that of a given source.

Cost information

The cost of a project including estimated costs and life cycle costs.

Design drawing

These include coordinated architectural-structural-building services-drainage-renewable energy system layouts, sections and site plans including owner, date, project reference, revision number and title.


Relative loudness of sound to the ear. This expression in decibels is weighted because the ear is less sensitive to low frequencies compared to higher ones.

Dedicated bicycle lane

Separately buffered, protected bike lanes typically demarcated with pavement markings, buffer zones and signage.

Design program

A schedule of all strategic dates of the design process aligned with the project program

Design responsibility matrix

Document clarifying who what when where. It presents the extent of any performance specified design.

Developed design

The detailed design proposals regarding form, layout, structural and constructional design, services, specs, costs based on concept design. Included within are updating the sustainability strategy, operation and maintenance strategy, handover, risk assessment, construction logistics, health and safety, third party consultation and research and development in line with the design.

Development user guide

Dedicated development, building or site-specific guidance for the non-technical user. Purpose is to help users access, understand and operate the development premises efficiently and in a manner in keeping with the original design intent. A development user guide should be written so that it will provide easily accessible and understandable information relevant to the following stakeholders:

  • The development's staff (or where relevant, residents)
  • The non-technical facilities management team or building managers
  • Other development users, e.g. visitors, community users
The content of the guide will be specific to the development type and end users, but broadly should include information on the following:
  • Overview of the development and its environmental strategy, e.g. energy or water or waste efficiency policy or strategy and how users should engage with and deliver the policy or strategy
  • Building services overview and access to controls, e.g. where to find them, what they control, how to operate them effectively and efficiently etc.
  • Pre-arrival information for visitors, e.g. access and security procedures and provisions
  • Provision of, and access to, shared facilities
  • Safety and emergency information and instructions
  • Development related operational procedures specific to the development type or operation, e.g. laboratories
  • Building related incident reporting and feedback arrangements
  • Provision of, and access to, transport facilities, e.g. public transport, cyclist facilities, pedestrian routes etc.
  • Provision of, and access to, local amenities
  • Re-fit, refurbishment and maintenance arrangements and considerations
  • Links, references and relevant contact details
Electronic benefit transfer (EBT)

System in the USA allowing state welfare issued via payment cards usable for food and cash benefits.

Elemental LCC plan

The plan assisting the development of solutions at a project's initial stage during options appraisals with costing based on a mix of typical benchmarks for key elements, comparative cost modeling and approximate estimates. It is measured in units of cost per square meter of gross internal floor area and considered at the elemental analysis in comparison to capital cost available.


The portion of energy (radiant heat in our cases) a material may emit when compared to the energy that would have been emitted by a black body of same temperature.

Environmental equity

Spatial distribution of greenery across an area ensuring this is evenly spread.

Environmental management system

An EMS may be developed following guidance in the WRAP publication 'Your Guide to Environmental Management Systems', at the WRAP website. Although a UK based document, this guide follows requirements of ISO 14001 and EMAS; however certification against ISO 14001, EMAS or the equivalent standard will be required to demonstrate compliance with the sustainability feature regarding EMS on our 'responsible construction' web page.


The Energy Performance of Buildings Directive is the main legislative instruments that promotes energy performance of buildings and is responsible for boosting renovation within the EU.

Equity (in finance)

Ownership of assets that may have liabilities i.e. debts attached. It is measured by subtracting liabilities from asset value. Equity may account to a single asset like a car, or house but also to an entire business.

Equity funding

Process of raising capital via i.e. sale of shares thus selling ownership in return for cash.

Equity free funding

Funding without an exchange of equity. Some incubators and government organizations provide funds that comprise essentially a grant, rather than an investment. It still comes with strings attached i.e. in the form of frequent and detailed reporting requirements to provide mentoring/advising to future participants.

Essential mental health services

These include early identification - treatment of disorders, management of psychiatric patients, counselling of common disorders, referral to specialists and mental health promotion - prevention activities.

Exclusive breastfeeding

Feeding infants only breast milk in line with suggestion from the WHO, UNICEF and American Academy of Pediatrics for optimal growth, development and health.

Fabric energy efficiency

The ability of a building's shell to maintain the desired indoor conditions regarding temperature, air quality, lighting and relative humidity depending on the energy consumption required. It is directly related to all the building's construction element U-Values, thermal bridging, infiltration rate/air permeability, thermal mass levels, solar, metabolic, lighting and appliance gains.

Feasibility study

A report that investigates the financial viability of the initial project brief for the particular site and how some site-wide matters will be addressed.

Formally agreed

Performance targets agreed via letter of appointment between design team lead and other members.

Food insecurity

A social and financial condition regarding limited - uncertain access to food.

Green roof system

A vegetation layer on a rooftop for thermal insulation i.e. cooling and energy management. The design included a minimum of 2-inch covering of hard ground cover and may include additional features as park and trees.

Green space

An environment containing vegetation e.g. trees, grass, forests, parks, gardens.

Health disparities

Different health status of various groups of people.

Health impact assessment (HIA)

Evaluation of the effects of a plan, project or policy prior to implementation which may lead to further considerations regarding the decision making process especially aspects that may fall out of the typical public health arenas i.e. transportation and land use. A HIA offers practical recommendations to increase positive health effects and minimize the negative.

Heat exchanger

In buildings this relates to devices that assist in absorbing heat or coolth from the stale indoor air and transferring it through their large surface area to the fresh air supplied from the outdoors in order to reduce the energy required to bring that fresh air to the appropriate temperatures required indoors.

Heat Pump

Heating and cooling systems powered usually by electricity. They operate in a similar manner as a refrigerator, through extracting heat/coolth from a lower/higher temperature source i.e. the ambient air or gro amount of electrical power consumed is usually much less than half of the heating/cooling power generated.


Heat loss parameter in buildings regards the loss through fabric and due to ventilation divided by floor area.

Incidental gains

Heat sources in which the heat is a byproduct to the main function or activity i.e. occupant latent and sensible heat, electric appliances and lighting.

Independent party

A person or body not involved in a particular design issue who does not have any conflict of interests due to their position within the project.

Internal rate of return (IRR)

Helps investors measure project profitability.
It's a ratio equating the present value of cash inflows (benefits) with those of outflows (costs).
It is basically a ratio for which NPV (Net Present Value) of an investment turns into zero.
'Internal' means the rate depends only on the investment's cash flows.
In the study of bonds, we encounter IRR under 'yield to maturity'.


Interstitial condensation

The type of condensation occurring within any of the construction materials.

Inverted roof

A roof design where thermal insulation is placed above the damp proof membrane leaving it exposed to water.

Key meetings between project team and stakeholders

Meetings including decisions that are crucial to the design and construction with impact on sustainability. Parties included may include client or developer, principal contractor, architect, structural engineer, services engineer, cost consultant, environmental consultant, project manager, access consultant, asset manager, leasing agent.

Key phases

Project important phases including concept design, developed design, construction stage, commissioning and handover, in-use occupation stage.

The key sustainability fields

  • Improving energy performance by increasing fabric efficiency thus reducing demmand
  • Reducing water consumption
  • Minimizing construction and operational waste
  • Reducing embodied impact of materials
  • Designing for resilience via flood prevention and tackling climate change
  • Sources of pollution prevented /mitigated
  • Sustainable means of transport for building users
  • Occupants' health and wellbeing
  • Ecological impact of development
Overall performance is based on appropriate minimum standards against fundamental environmental issues and features combined with a balanced scorecard approach to allow a degree of flexibility in response to local needs. In addition, each of the key sustainability fields are weighted to reflect their special weight in the local context.

Legally harvested and traded timber

Legally harvested timber and wood-derived products originate from forests with the following criteria:

  • Forest owner/manager holds legal use rights to the forest
  • There is compliance by both the forest management organization and any contractors with local and national legal criteria including those relevant to:
    • Forest management
    • Environment
    • Labor and welfare
    • Health and safety
    • Other parties' tenure and use rights
    • All relevant royalties and taxes are paid
  • Full compliance with the criteria of CITES
Legally traded means timber or products derived from Legally harvested timber were:
  • Exported in compliance with country laws governing the export of timber products, including payment of any export taxes, duties or levies
  • Imported in compliance with country laws governing the import of timber products, including payment of any import taxes, duties or levies
  • Traded in compliance with legislation related to the convention on international trade in endangered species (CITES), where applicable
Life cycle costing - LCC

A methodology which systematically evaluates the financial cost of an asset and its parts throughout its life (by life is meant a period in which an asset fulfills its performance requirements and the period is defined as such within the agreed scope).

Linear thermal transmittance - Psi

The heat loss due to thermal bridging named 'Psi' defined as the heat flow per degree C per unit length of the bridge and measured in W/mK.

Load compensator

Device that adjusts water temperature circulated in a heating system in accordance with indoor temperature specified.

Minimum consultation content

This is dependent on the development and scope of the project and includes:

  • Functionality, build quality and impact (including aesthetics)
  • Provision of internal and external facilities (for future occupants, visitors and users)
  • Management and operational implications
  • Maintenance resources implications
  • Impacts on the local community, e.g. local traffic and transport
  • Opportunities for shared use of facilities and infrastructure with the community and appropriate stakeholders, if relevant and appropriate to the development type
  • Compliance with statutory (national or local) consultation requirements
  • Inclusive and accessible design
In the case of educational building types:
  • How building and grounds could best facilitate learning
  • Where the scope of works involves changes to the internal layout and function, the consultation considers how the design can best provide a range of social spaces appropriate to the needs of pupils, students and other users
In the case of developments containing technical areas or functions, i.e. laboratories, workshops etc:
  • The end users' broad requirements for such facilities, include appropriate sizing, optimization and integration of equipment and systems

Mechanical ventilation heat recovery systems maintain heat/coolth of stale air extracted and feed it into the supply via heat exchange.

National health and safety regulations and best practice (Quality plan)

Where there are no national health and safety regulations in the country of assessment, evidence is required to demonstrate that

  • EITHER: Principal contractor has an occupational health and safety management system compliant with OHSAS 18001:2007
  • OR: Works carried out in accordance with the International Labor Association's Safety and health in construction Code of Practice
NOx Nitrous Oxide

NOx is a bi-product of the combustion process of fossil fuels which haw o global warming potential (GWP) 270 times that of carbon dioxide.

Passive solar design

A building design that focuses on utilising the sun for natural lighting and space heating but also sheltering from the sun when there is risk of overheating or glare.

Project delivery stakeholders

Parties that offer feedback from the earliest practical stage include the client, the occupier, the design team and the principal contractor (or a consultant experienced in contracting and construction).

Project Execution plan (Quality plan)

A plan produced by the project's leader and lead designer considering feedback from the other team members that sets out processes and protocols for the design development.

Project strategy

Strategies prepared same time as Concept Design to support and respond to project brief. Such strategies might relate to sustainability, accounts, maintenance and operation, handover, building control, fire engineering, health and safety, travel plan, sustainable procurement.


In building design this relates to thermal energy transferred to and from the building through long electromagnetic waves.

Relative humidity -RH

The portion of water vapour in the air compared to the maximum water vapour that the air can hold at a specific temperature.

Resistivity- R-Values

Thermal resistivity measures a material's ability to impede heat flow. R-Value is the opposite to the heat transfer coefficient (h=q/DT).

Risk assessment

A summary of all design risks and other risks on a project and who and how will handle these.


Stands for standard assessment procedure and is a number 1 to 100 that represents the cost per meter square of a home's energy consumption for space heating & cooling, DHW, ventilation, lighting.

Soft landing framework

Framework promoting good and well documented briefing, design, handover and in-use performance that can be used to prove i.e. sustainable design features have been complied with. This framework is prepared by Usable Buildings Trust (UBL) and Building Services Research and Information Association (BSRIA).

Solar panel - collector

Glazed panels that collect the sun's radiation and convert it into heat for domestic hot water purposes.

Standardized method for life cycle costing (SMLCC) for construction

Guide PD 156865:2008 details the way to procure SMLCC regarding construction with the aims being to deliver:

  • A British standard cost data structure regarding LCC in line with BS ISO 15686-5, Building Cost Information Service (BCIS), Standard Form of Capital Cost Analysis (SFCA) and industry recognized occupancy cost codes.
  • A standardized method to apply LCC for the UK construction industry and for the key stages of procurement.
  • A process on how to plan, generate, interpret and present results depending on the purpose and level of life cycle costing.
  • Instructions on what the particular requirements are depending on what is being assessed as well as the selection of the appropriate financial evaluation method.
  • Practical instructions, definitions and worked examples of LCC for construction.
  • An industry accepted methodology ensuring accuracy, consistency and the robust application of LCC analysis and benchmarking.
  • Clarity on the scoping and terminology.
Strategic performance targets

Goals laid down early in the design process set at a strategic level. They define aspirations and performance objectives broadly.

Strategic (initial) project brief

Document produced after discussions between client and design team to ascertain project objectives, the client business case also in response to site specific feasibility studies.


Is the natural and built fabric of each street, and is defined as the design quality of the street and its visual effect meaning how the paved area is laid out and treated. This includes buildings, street surfaces, fixtures and fittings that facilitate its use including bus shelters, signage to planting schemes.

Sustainability assessor's site inspection

A report based on the assessors on site survey to confirm compliance with sustainable features included within the design. This may include images accompanied by clarifications on how sustainability criteria have been satisfied.

Sustainability scheme compliant organizational, local or national considerate construction schemes

Where a considerate construction or constructors' scheme exists and is not listed as a compliant scheme, the scheme administrator or operator can apply to some sustainability schemes for recognition as a compliant scheme.

Thermal break

A thermal insulating layer on the metal frame of a window or door which reduces heat loss and thus the U-Value.

Thermal bridging

The path within a building's construction element where heat is dissipated through a material of considerably lower thermal resistance (higher conductivity) to the surrounding materials of that construction element e.g. steel wall ties through insulation.
Repeated bridges are paths evenly spread within the construction and thus can be included within the overall construction's U-Value calculation i.e. rafters penetrating the insulation layer of a sloped roof. Guidance may be acquired within the BRE's publication 'BR443'.
Non repeating bridges are paths that occur at junctions between building elements, e.g. at wall to roof or wall to floor locations or on the windows perimeter where the insulation continuity or levels is interrupted or compromised. These paths increase apart from heat loss, the risk of condensation. In highly insulated homes, a large portion of the total heat loss is attributed to this type of thermal bridging.

Thermal conductivity - K

A material's thermal property describing how easy it is for heat to be transferredthrough it under particular climatic conditions and is measured in W/mK.

Thermal efficiency (i.e. of a boiler)

The ratio of heat warming cold water before entering the distribution system to the energy within the fuel prior to usage.

Thermal mass parameter

In thermal modeling this is the sum of areas of a particular construction element multiplied by their admittances divided by the total area in order to measure the extent to which heat can be absorbed and stored and is measured in kJ/m2K.

Thermal performance

The ability of a building's shell to maintain desired indoor climatic conditions. The heat loss rate depends on the physical properties of a building's construction elements as far as insulation levels are concerned, plus the physical dimensions, orientation, ventilation levels, glazing properties, shape and size, shading devices etc.

Thermographic survey and air leakage testing

The thermographic survey must cover 100% of the treated spaces, unless it is a large complex building, and ensure that all elements of the building fabric that enclose an internal conditioned zone of the building are tested. In the case of large and complex buildings, e.g. airports, larrge hospitals and highrise buildings based on a Class/Category II thermographic surveyor, the guidance in air tightness standard ISO 9972:20155 should be followed on the extent of the survey and testing.

Appropriate standards for thermal imaging and air leakage testing are ISO 6781-3:2015 Performance of buildings - Detection of heat, air and moisture irregularities in buildings by infrared methods – Part 3: Qualifications of equipment operators, data analysts and report writers.

ISO 6781:1983 Thermal performance of buildings - Qualitative detection of thermal irregularities in building envelopes - Infrared method.

ISO 9972:2015 Thermal performance of buildings - Determination of air permeability of buildings - Fan pressurization method.

Regarding the requirement for a thermographic survey AND air tightness testing, this consists of ensuring continuity of insulation, avoidance of thermal bridging and air leakage paths. Achieving this is up to the suitably qualified professional. There is no requirement to carry out both, unless this has been deemed necessary by a suitably qualified professional.

Finally, the thermographic survey is normally undertaken by a suitably qualified professional classified and qualified as a Class/Category II in thermography.

Suitably qualified professionals regarding thermographic survey and airtightness testing are the following:

  • Airtightness testing-professionals with membership of an organization maintaining accreditation by the relevant Accreditation Body (to fulfil the requirements of ISO 17024), or a nationally recognized competent persons' scheme, e.g. ATTMA.
  • Thermographic survey-professionals holding a valid Category II in thermography, as defined by ISO 18436-7:2014 or Class II in infrared thermography as defined by ISO 6781-3:2015.
Transmittance factor - g

The percentage of incident solar radiation on the window pane that is transmitted through the window indoors. This number varies from 0-1 from no light entering to 100% of light entering a building.


A figure describing the rate of heat transferred through a construction element measured in W/m2K.

Warm roof

A roof in which thermal insulation has been placed exactly underneath the waterproof membrane at rafter level meaning any space within the roof will remain warm.


The overall heat transfers due to non-repeating thermal bridges equal to the sum of linear thermal bridge values multiplied by their lengths divided by the Total Heat Loss Area of the building.


1. Commercial energy assessor's handbook. Larry Russen, Simon Rees & Stephen Neale.
2. BREEAM NC, BREEAM RFO, BREAM communities manuals (Building Research Establishment Environmental Assessment Method).
3. International Well building institute. Well building standard.
4. The Government's Standard Assessment Procedure for Energy Rating of Dwellings, 2012 edition. BRE.
5. National Home Energy Rating (NHER) energy assessment scheme. National Energy Services Ltd (NES).
6. A technical manual for SBEM. Communities and Local Government. UK Manual.
7. Home Quality Mark ONE SD239. Technical Manual for England, Scotland and Wales. BRE
8. C. Charlwood Torbay Streetscape Guidelines Torbay Council, Torques (2004) pp. 11-13


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