Specification of low emitting materials
Using low emitting products can significantly reduce VOC concentrations indoors
Some examples include:
- water or vegetable oil based paints and stains stating a low VOC content;
- building materials and furnishings which are certified to emit low levels of VOCs such as linoleum, seagrass and wool carpets;
- biodegradable detergent-based cleaners, favouring those that are not fragranced and rubbed rather than sprayed; and
- furnishings made from solid wood instead of pressed or reconstituted wood. Pressed wood is often bound with chemicals such as formaldehyde. In the case that pressed wood cannot be avoided, a viable solution is to seal pressed wood with formaldehyde sealing coatings.
For more information refer to the Materials module.
BREEAM and HQM credits are available where total VOC concentration is measured at below 0.3mg/m3 over 8 hours.
Aerosols and other fragranced products which add additional VOCs into the air should be minimised and chemicals such as opened pesticides and paints should never be stored indoors or in air handling rooms of commercial buildings.
Building services specification and maintenance
Building services should be designed in line with best practice guidance, such as that produced by the Chartered Institute of Building Services Engineers (CIBSE) for elimination of Legionnaire’s risk.
Building services should also be designed with Planned Preventative Maintenance (PPM) in mind. Well maintained building services perform better and consequently ventilation, humidity levels, energy consumption etc. are optimised. The key consideration in maintaining building services is ease of access. Building Information Modelling (BIM) is a process for creating and managing information on a construction project across the project lifecycle and can help to improve maintenance and life time building use.
Where necessary, specification of ultra-low NOx boiler systems or CHP should be included. Typically a dry NOx level below 40mg/kWh is considered best practice. .
After removing pollutant sources as far as practicable, adequate ventilation is the next most significant element to consider in maintaining internal air quality.
Recommended ventilation rates for rooms vary, depending on room function, the type and age of building, number of occupants, etc. Part F of building regulations includes minimum extract rates for a range of building types. Too much ventilation results in poor comfort for building occupants, and increased energy consumption. To reduce energy consumption, heat exchangers can be used to preheat incoming air. Air can also be recirculated to reduce heat loss, typically seen within Passivhaus developments.
Typically, natural ventilation solutions consume less energy than sealed buildings. However, natural ventilation cannot always be pursued if, for example, the building is adjacent to a source of air (or noise) pollution, such as a major road or industrial process.
In cases where natural ventilation is not feasible mechanical ventilation with heat recovery (MVHR) can offer an energy efficient solution. To enable MVHR systems to work effectively a low air permeability is required.
Control of refrigerant emissions
A number of systems are available that monitor the accidental release of refrigerants from air conditioning plant. These include:
- refrigerant detectors – including infra-red, semi-conductor and electro-chemical detectors that link to a central alarm unit
- indicator dyes – fluorescent or coloured dyes added to the refrigerant to show leakage sites
- halide torch detectors – only appropriate for chlorine based substances such as CFCs or HCFCs
All of these systems work better when an air conditioning plant is contained in, for example a basement rather than exposed on a roof.
To allow the BREEAM leak detection credit to be awarded a permanent automated leak detection system is required which is capable of isolating and containing the remaining refrigerant charge.
Construction Site Dust and Air Pollution
Construction and demolition activities can generate signficant air quality problems. However, best practice control measures are easy to implement and guidance is widely available. Construction site dust typically comprises small particles such as soot and cement and larger particles such as grit, sand and wood dust.
Local Authorities can impose conditions upon construction operations as part of the planning process and can require works to avoid a statutory nuisance under the Environmental Protection Act 1990 (which requires implementation of Best Practicable Means to control dust). A Committee of the House of Commons has released a report calling for the government to pass a new Environmental Protection Act, before the UK leaves the EU.
Best practice guidance is available from Institute of Air Quality Management.
In addition to adhering to Local Authority requirements, contractors are also recommended to sign up to the Considerate Constructors Scheme a non-profit, and independent organisation founded by the construction industry to improve its image.
The Scheme covers all aspects of the way a site is run, from the way the site is presented through to issues such as air quality. Registered sites are required to adhere to the Scheme’s 5 part Code of Considerate Practice and are assessed by one of the Scheme’s experienced Monitors, with the aim of improving the image of construction through:
- ensuring sites appear professional and well managed
- giving utmost consideration to their impact on neighbours and the public
- protecting and enhancing the environment
- attaining the highest levels of safety performance
- providing a supportive and caring working environment
All registered sites must clearly display Considerate Constructors Scheme posters, providing a project name and local number and details of the Scheme’s administration office, web address and telephone number.
If the Scheme receives a complaint about a registered site, the details are logged. The Site Manager is informed about the nature of the complaint and is expected to deal with the complainant’s concerns. If a complaint is not dealt with adequately, the complaint will be passed to a higher level within the construction company, to ensure that it is addressed.
The Scheme’s overall aim is to promote good practice and improve the image of the construction industry.
Good environmental site practice includes the following:
- identifying dust generators and sensitive receptors (e.g. housing and ecological resources) and distance dust generating activities appropriately from these sensitive receptors
- wheel washing all vehicles
- dampening and sweeping roadways
- covering vehicles and skips when loaded with material
- locating (dampened) stock piles to take account of prevailing wind/sensitive receptors
- sealing and replanting completed earthworks as early as practicable
- dampening stone cutting
- using low emission vehicles and plant equipment (particularly on site generators)
Best practice Air Quality publications can be found in the Further Information and References Section.