Meeting the needs of Sustainability
By Ian Davis, technical and quality manager at Vortice
Probably the single most important issue facing the ventilation industry today is energy efficiency and carbon reduction and housebuilders everywhere are looking for cost effective means of achieving the best possible ratings which comply with required standards.
The base standard for CO2 emissions in new dwellings is defined in The Building Regulations Approved Document L1A 2006 Conservation of fuel and power in new dwellings (ADL). Other sections of ADL, which is split into four sections, cover existing dwellings and buildings other than dwellings. For new dwellings, the annual CO2 emission rate of the completed dwelling, the Dwelling Emission Rate (DER) must not exceed the target set by reference to a theoretical building, the Target Emission Rate (TER).
Emission Rates are expressed as the mass of carbon dioxide in kilograms emitted per square metre of floor area per year as a result of the provision of heating, cooling, hot water, ventilation and lighting, assuming a standardised household. The ADL was issued by the Department for Communities and Local Government as part of the Government’s drive to improve our environmental credentials. The Code for Sustainable Homes followed this and sets out six target levels for improvement on the ADL requirements; called the Sustainability Rating System.
Level 3 of the code is defined by the Energy Saving Trust’s (EST) Best Practice standard for energy efficiency, and represents a 25 per cent improvement over ADL – level 6 calls for zero carbon emissions. All publicly funded Social Housing new build has to achieve a minimum of level 3 and because many developers build for the social sector, they have to provide dwellings to this standard – the Dwelling Emission Rate must be a minimum of 25 per cent lower than the Target Emission Rate.
So, if a theoretical dwelling had a Target Emission Rate of 24 kilograms of carbon dioxide emitted per square metre of floor area per year, then in order to achieve Level 3, the Dwelling Emission Rate must be no more than 18 kg per year. Best Practice is not only about ventilation requirements and compliance may be demonstrated also by taking into account additional factors such as U-values, air permeability and lighting in order to achieve improvements on CO2 emission rates. For example the improvement on CO2 emission rates could be achieved by means other than selecting an improved ventilation system.
Meeting the standards
These construction standards are required because compliance with Best Practice could otherwise be achieved for example, by specifying a wood stove in a very poorly constructed dwelling. The EST’s document GPG268 Energy Efficient Ventilation in Dwellings – A Guide for Specifiers details the ventilation requirements for compliance with the Good Practice and Best Practice performance standards.
The Good Practice standard represents an improvement on Building Regulations principally in insulation; heating and air tightness and any ventilation system in compliance with Building Regulations Approved Document F1 (2006) Means of Ventilation (ADF) can be used.
The Best Practice performance standard represents a readily available higher standard and if an improved ventilation system is chosen in order to meet the standard, the ventilation options are limited to continuously running extract only fans (MEV or continuously running fans) and MVHR (ADF systems 3 & 4, respectively). Compliance to these criteria is demonstrated by having product tested to Standard Assessment Procedure (SAP) Appendix Q (SAP Q) test procedures.
In general, a technology may use one form of energy (e.g. electricity) to achieve savings in another form of energy (e.g. gas or oil, in heating). As a consequence continuously running extract only fans (MEV or single-room units) and MVHR are the only two forms of ventilation accepted to improve the efficiency calculation of the dwelling and the only two forms of ventilation that SAP Q can be applied to.
The scheme is currently operated by the Building Research Establishment (BRE) and the Vortice Prometeo Heat Recovery unit and Vortice Centralised Ventilation Extractor are two Vortice SAP Q Eligible products. There is of course, no such thing as a SAP Q approved product, as the rating depends on so many other factors, but products designed to be ecofriendly may be Appendix Q Eligible.
The SAP Q Calculation Spreadsheet outputs energy saved and energy used data that the SAP Assessor then inputs into a SAP Q section of the SAP Worksheet. The SAP Worksheet then takes this information into account in calculating the Dwelling Emission Rate (DER). Of course it also takes many other factors into account, such as wall constructions, windows, lighting, etc. The SAP Assessor finally compares the calculated Dwelling Emission Rate (DER) with the Target Emission Rate (TER) to ensure that the required improvement over ADL (a 25 per cent reduction if the dwelling is being built to the Code for Sustainable Homes Level 3) is reached.
Updating the industry
Vortice runs regular CPD seminars specifically aimed at updating architects, specifiers and installers on issues affecting domestic ventilation systems and compliance with Building Regulations.
Vortice seminars give a thorough overview of the subject and covers topics like the importance of good ventilation in domestic dwellings, correct design and installation techniques, the Code for Sustainable Homes, health and safety issues on site and cost comparisons between systems 1, 3 and 4.
Bringing the best new models to the market with the highest possible energy efficient ratings is Vortice’s stated aim and true to form, they launched a new SAP Appendix Q eligible Mechanical Extract Ventilation fan at ISH.
The Vort Leto MEV offers a cost effective means of achieving the best possible ratings which comply with the required standards. One fan ventilating the entire property requires only one connection to the mains supply and remote frequency (RF) control options cut out the need to route cables to the switch. Vort Leto is available in the UK in two models: a hard wired and RF (radio frequency) remote unit. Both models are fully compliant with the requirements of Building Regulations Approved Document F (2006) System 3 – Continuous Mechanical Extract Ventilation. The Vort Leto is also Energy Saving Trust Best Practice Performance Compliant.
The company’s newest launch is Vort Notus, a de-centralised continuous mechanical axial extract fan. Particularly useful for refurbishments and for social housing applications, the Vort Notus works on a simple ‘one fan for any room’ basis and is SAP Q eligible. A simple pin mechanism in the back enables the installer to change the performance of Notus according to which room it will be based in; settings run from 5 litres per second to 10 litres per second with a 15 litres per second boost. Vort Notus’ constant airflow control ensures the nominal performances in a wide range of alternative situations; one single fan is for wall, ceiling and in-duct installations.
Versatile designs incorporated into the entire range of Vortice products ensure minimal labour costs and a fast installation learning curve. The company’s experienced technical department offers a reliable and friendly design and advice service to help ensure that the correct product is specified for the project in hand.