Appendix - Weil-McLain WTGO Series Manual

Combustible Surface
Protection
Type "L" Doublewall
Vent Piping
Flue Pipe Clearances
24" For Servicing
or Min. 2" for Close
Clearances
2"
NOTE: 2" Min. on Sides
Back Vent Clearances
FIGURE 21

Appendix

A
6"
6"
FIGURE 20
A
Combustible
Surface
Combustible
Surface
PROTECTION REQUIRED FOR CLEARANCES LESS
THAN 6 INCHES FROM DOUBLEWALL VENT PIPE*
Dimension A
When desired minimum
clearance from Type "L"
doublewall vent pipe to
combustible surface is:
3"
2"
3"
* All clearances measured from outer surface of equipment to combustible surface,
not to the protection used.
* * Apply to combustible surface unless otherwise noted. Cover all surfaces as
specified in Table and FIGURE 20. Thicknesses are minimum.
* * * Factory-fabricated board made of non-combustible materials, normally fibers,
having thermal conductivity in range of one (Btu-inch)/(hr./sq. ft./°F) or less.
+ Mineral wool batts (blanket or board), having min. density of 8 lb/ft3 and a min.
melting point of 1500°F.
OTHER DIMENSIONS AVAILABLE. REFER TO NFPA-31.
Combustible
Surface
A
2"
CONTINUED
Use the following
protection**:
½" thick insulation board ***
over one-inch glass fiber or
mineral wool batts+
24 gauge sheet metal with
one-inch ventilated air space
½" thick insulation board * * *
with one-inch ventilated air space
A
A
24" For Servicing
or Min. 2" for Close
2"
Combustible
NOTE: 2" Min. on Sides
Top Vent Clearances
FIGURE 22
Clearances
Surface
27