appliance isolation valve – numbering & design

To help ensure effective use of isolation valves it's recommended that those which are not immediately adjacent to appliances should be clearly marked to the appliance they serve.

For ease of use if valves operate by rotation it's recommended that they are closed by turning clockwise. It's also a good idea to mark the 'open' and 'closed' positions on or next to each of the valves on your boat.

Using unsuitable valves can allow gas to leak. Plug valves must be springloaded and needle valves must not be used.

Accidentally switching a valve on could lead to an unnoticed accumulation of gas. To help prevent this happening, valves at floor level must be located so they can't be inadvertently activated, or they must be of the drop fan or loose key type.

If pipework is not sealed effectively from appliances which have been permanently removed or temporarily removed for servicing, gas will leak. To prevent this from happening, pipework to such appliances must be properly plugged or capped. Isolation valves alone are not sufficient for this purpose. [7.21]