An intumescent seal is an integral part of a fire doorset. It remains dormant under normal conditions but swells to many times its original size when exposed to the heat of a fire, thus closing the gap between a fire door and its frame. Intumescent seals are frequently combined with cold smoke seals, which latter prevent the ingress of smoke around fire door edges in the early stages of a fire.
|IP #||First Number - Protection against solids||Second Number - Protection against liquids||Third Number - Protection against mechanical impacts (often omitted)|
|0||No Protection||No Protection||No Protection|
|1||Protected against solid objects over 50mm||Protected against vertically falling drops of water||Protected against impact of 0.225 joules|
|2||Protected against solid objects over 12mm||Protected against direct sprays up to 15 deg. from vertical||Protected against impact of 0.375 joules|
|3||Protected against solid objects over 2.5mm||Protected against direct sprays up to 60 deg. from vertical||Protected against impact of 0.5 joules|
|4||Protected against solid objects over 1mm||Protected against direct sprays from all directions - limited ingress permitted||Protected against impact of 2.0 joules|
|5||Protected against dust - limited ingress permitted||Protected against low pressure jets from all directions - limited ingress permitted||Protected against impact of 6.0 joules|
|6||Totally protected against dust||Protected against strong jets from all directions - limited ingress permitted||Protected against impact of 20.0 joules|
|7||Protected against effects of immersion from 15cm - 1m|
|8||Protected against long periods of immersion under pressure|
|9k||Protected against close-range, high pressure, high temperature spray downs|
For example IP65 would be interpreted for protection as follows: 6 (being the first number of the code, the number relates to the second column in the table) - Totally protected against dust, and 5 (being the second number of the code, the number relates to the third column in the table) - Protected against low pressure jets of liquids from all directions - limited ingress permitted.
This system is designed for IP ratings of up to three digits.