Many schools in the past have been caught off guard and suffered burst pipes causing flooding to classrooms and collapse of ceilings, damage to furniture and equipment etc. The cost of repair in many cases can be very substantial. A surprising aspect of many of these claims is that many of these schools had only been built in the last five to ten years and should, therefore, have had adequate insulation for pipes. Poor or no insulation of the cold water supply to storage tanks in attics and central heating frost thermostats incorrectly set or turned off were the main contributory factors.
Shown below are some precautions you should take to avoid frost damage to hot water heating systems, water services and also subsequent water damage to buildings and contents, during such weather.
- Ideally heat should be maintained in the building during periods of severe cold weather
(a) If the heating system is fitted with a frost thermostat, ensure that it is correctly set, i.e. 35°F or 2°C if located indoors, or 32°F or 0°C if outdoors. Test its effectiveness by setting it at the surrounding temperature. If the system does not start up have it checked by an engineer.
N.B. If a frost switch is fitted, this puts either the frost thermostat or time switch in control of the heating. There is no protection unless the switch is in the 'Frost' position.
(b) If the heating system in the school has no frost thermostat fitted, the system should be started manually and checked periodically by a responsible person and kept running long enough to keep temperatures in the building and the boiler room at a safe level.
- Remember to protect your oil supply against freezing. Precautions listed above will be ineffective if the oil is frozen and cannot reach the boiler. This may happen if temperatures of 12°F or -9°C prevail. The oil supply pipe can be protected with weatherproof insulation and a tarpaulin cover will provide emergency protection to the tank.
- Where the heating system is used, internal doors should be left open to protect unheated or poorly heated compartments, but always subject to applicable fire safety rules and regulations which should take precedence. Make sure all radiators are on.
- If air vents in the boiler room are closed off, leave sufficient opening to allow an adequate supply of air for combustion.
- If the system is not to be kept running during periods of severe cold, the entire system (including the boiler) must be drained. Remember to open radiator vents to ensure complete drainage.
- Where the system is drained or the building is otherwise unheated, all sanitary and domestic water services should be drained by shutting off at the main and running and flushing off all water in pipes, tanks and cisterns. In these circumstances, outside toilets and pump houses should be similarly protected.
- Make sure that all tanks and pipes in the roof space and all external vent or expansion pipes are well lagged or insulated.
NOTE: When a heating system is drained, switch off at the main switch and place a prominent notice on the switch stating - SYSTEM DRAINED - DO NOT START.
The information provided here is intended for use as a guideline only in assisting schools to assess preparedness for frost conditions during severe or prolonged cold weather and to encourage appropriate preventative measures.