Update to Visqueen Gas Venting Specification Tool

The hazards of ground gases and volatile organic compounds (VOCs) must be taken into account when designing and constructing developments on gas contaminated land. The Visqueen Gas Venting Guide has been updated to include information on Volatile Organic Compounds (VOCs) and Hydrocarbons, including the protective measures required as determined by CIRIA 716.

gas venting guide

Volatile Organic Compounds (VOCs) are commonly found on land affected by contamination in the UK, at concentrations that result in the need for remediation and risk mitigation measures to be carried out to manage the potential risks to people.

Whist there has been a broadening in the range and complexity of remediation and risk mitigation techniques over the past few years, there is a lack of guidance specifically aimed at remediation and mitigation of risks arising from VOCs and Hydrocarbons.

Visqueen’s updated guidance is designed to provide architects, specifiers and other building professionals with a comprehensive information tool for understanding gas venting categorization and the protective measures required in relation to VOCs and Hydrocarbons. The aim is to remove the complexity of design and specification by providing a user friendly tool that presents detailed technical information in a clear, logical manner.

BS 8485:2007 Code of practice

The updated guidance walks you through the step-by-step chronological process of site categorisation, hazard potential, building type and finally the protective measures required to mitigate the presence of ground gas on site. If Hydrocarbons or VOCs are present, an additional risk assessment is required in accordance with CIRIA C716 – see page 4 of the updated Visqueen Gas Venting Guide for more information.

CIRIA C716 – Mitigating risks from VOCs on gas contaminated land

CIRIA C716 gives clear and flexible guidance specific to the management of VOC vapours. Based on these guidelines Visqueen has adopted the following procedure:

Visqueen Guidelines for Hydrocarbons and VOCs

• If Hydrocarbons or VOCs have been detected then an additional risk assessment is required for the Hydrocarbons or VOC. This risk assessment must be completed in accordance with CIRIA 716.

• If the detected VOCs are deemed a low risk in accordance with CIRIA C716, and the design team require a VOC decay resistant membrane, then the most suitable membrane is: Visqueen GX Flexi Hydrocarbon Barrier.

• When bulk gases or VOCs are present in ground bearing slabs then a ventilation system is required.

Visqueen’s complete Gas Venting system enables the safe dilution and dispersal of harmful gases from beneath buildings, with a variety of compatible outlets and fittings to suit different building types and levels of contamination.

For further advice and design considerations please contact Visqueen’s Technical Support team.

You can view the Visqueen Gas Venting systems on our website, by clicking here and the updated guide can be downloaded here: http://www.visqueenbuilding.co.uk/download_file.asp?id=2042

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