- (a) A fusible plug, if used, shall be placed at the lowest safe water line and in contact with the products of combustion.
- (b) Any or all of the fittings and appliances required by this part may be installed inside the boiler jackets provided the water gauge and try cocks on a steam boiler are accessible without the use of tools and provided the water gauge and pressure gauge on a steam boiler or the thermometer and pressure gauge on a water boiler are visible through an opening or openings at all times.