Plumbing insulation – or lagging – performs two important purposes: it prevents pipes from freezing and bursting in cold weather and reduces heat loss as hot water moves through the system. The four main types of insulation used in plumbing are explained below.
Self-adhesive foam wrap
Supplied in 5m (16ft 6in) or 10m (33ft) rolls, this is a thin foam wrap 50mm (2in) wide, that is extremely useful if the pipe run includes a series of bends. Before the foam wrap is applied make sure the pipe is clean and dry. To apply, cut the foam wrap into manageable lengths, remove the backing paper and wind it around the pipe, overlapping by approximately one third of the width of the wrap.
Plastic foam tube
This is the most common form of pipe insulation and is made up of lengths of plastic foam tubing split down one side. By carefully opening the plastic foam tube at the split it can be eased on to the pipe, securing it in place at regular intervals with adhesive tape. Plastic foam tubes are manufactured to fit 15mm, 22mm and 28mm pipes and with a choice of two wall thicknesses.
The standard thickness will be sufficient for most pipe systems, but if you live in a location where the weather is particularly cold, or the pipes are exposed, then the thicker grade should be used. Although plastic foam tubing is a little more expensive than self-adhesive foam wrap, it is easier to use.
Boxed in pipes can be insulated by pushing glass fibre insulation blanket around the pipes.
Cylinder jackets are used for insulating hot water cylinders. Jackets are available in a range of sizes and can be between 75mm and 100mm (3in to 4in) thick. Most cylinder jackets are made up of a number of segments of mineral fibre enclosed in plastic, held together by a cord that is threaded through holes at the top of each segment around the top of the cylinder. When the cylinder jacket is in place it is held in position by a number of belts that fit around the tank.
When buying a cylinder jacket make sure it carries the British Standard Kite mark.