Series WTH
Page 8
LT105 Feb. 2019
Clearance to Combustibles
A general clearance of 18 (0.5 m) in every direction
is recommended for servicing only around each Burner and
air supply (at the far end of each radiant tube). Also, to ensure adequate air flow in and around the Heating System.
In addition to this it is very important to observe the minimum clearance to combustibles at all times to
avoid any possibility of property damage or personal injury.
WARNING
Clearances as marked on the heater body must be maintained from vehicles parked beneath. Signs should be
posted identifying any possible violation of the clearance distances from the heater in all vehicle areas.
Maximum allowable stacking height in storage areas should be identified with signs or appropriate markings
adjacent to the thermostat or in a conspicuous location.
Table 2 lists the minimum clearance to combustible materials for various installation configurations. Note that
standard clearances also apply to installation above T-bar ceilings and above decorative grills. Additional clearance
may be required for glass, painted surfaces and other materials which maybe damaged by radiant or convective
heat.
Combustible materials are considered to be wood, compressed paper, plant fibres, plastics, Plexiglas or other
materials capable of being ignited and burned. Such materials shall be considered combustible even though flame-
proofed, fire-retardant treated or plastered.
Elbows and U-bends are un-heat treated aluminized material and are typically installed without reflectors. Reflector
miter kits are available for U-bends and elbows.
Adequate clearance to sprinkler heads must be maintained.
The stated clearance to combustibles represents a surface temperature of 90°F (50°C) above room temperature.
Building materials with low heat tolerance
(i.e. plastics, vinyl siding, canvas, tri-ply, etc.)
may be subject to
degradation at lower temperatures.
It is the installer’s responsibility to ensure that adjacent materials are
protected from deterioration.
Note 1:
Bottom Shields are approved for all burner sizes. The below clearance (dimension C in Table 2) may be reduced by
25% when an approved Bottom Shield is used
.
Note 2:
Reduced clearances downstream from the burner are approved for all configurations. Dimensions B, C, and D in
Table 2 can be reduced for locations 25' (7.6 m) or more downstream from a burner maximum reduction is 50%