The dimensions given for firestop seal solutions are based on the outside diameter (OD) of pipes as they are installed around the outside of the pipe and need to suit the maximum measurement – and this is measured in metric (millimetres).
Some pipes are sold by their internal measurement so allowance for the wall thickness of the pipe needs to be taken into consideration when choosing firestop solutions.
Likewise, some pipes are sold – or known – by imperial measurements so an accurate calculation or measure needs to be undertaken.
As an example, a so called ‘2-inch pipe’ may calculate to a 50mm diameter but bearing in mind the wall thickness of the pipe, this is actually likely to be a 55mm outside diameter requiring a QWR55/CE Fire Collar and not a QWR50/CE.
Please don’t hesitate to contact us if you have any further questions.
