28. Hygrometer not to be affixed to wall, etc., unless protected by wood.
(1)No hygrometer shall be affixed to a wall, pillar, or other surface unless protected therefrom by wood or other non-conducting material at least half an inch in thickness and distant at least 2.5 cm. from the bulb of each thermometer.(2)No hygrometer shall be fixed at a height of more than 1.65 m. from the floor to the top of thermometer stem or in the direct draughts from a fan, window or ventilating opening.
