Traffic light classification

For low-rise housing with gardens, where a ventilated underfloor void is provided, the CSV is used in Table 6.4 (see colour section) to determine the level of risk (traffic light classification green to red). 

Once tire traffic light classification has been determined the appropriate level of protection can be defined using the NHBC guidance or CIRIA C659/665 (Boyle and Witiierington, 2007 Wilson et ah, 2006, 2007). The requirements are summarised below ... 

The traffic light classification is provided to give an indicative comparison only as the actual boundaries between the levels are different (see Box 6.3). The traffic light classification is restricted to low-rise housing with a ventilated underfloor void. 

Traffic light classification Methane Carbon dioxide ... 

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