Masonry Fireplace
Clearance to Combustibles Test

Introduction:

Efforts are under way to update the clearance to combustibles requirements for the ASTM Guide to Solid Fueled Masonry Heaters.

Jerry Frisch supplied the data below from the recent clearance to combustibles tests on a standard masonry fireplace, built to code, at OMNITEST Services.

This testing was funded principally by The Brick Industry Association (BIA) and Western States Clay Products Association (WSCPA). Additional funding and resources were provided by The Masonry Heater Association (MHA), Jerry Frisch, and Jim Buckley.

These results are preliminary.

Conclusion:

The highest surface temperature reached on the masonry fireplace back was 239F, using a UL-127 fueling protocol (See description in OMNI draft protocol and comments, below).

ASTM E1602 currently specifies a maximum surface temperature of 230F for masonry heaters, with unspecified fueling.

Description:

Back of fireplace showing thermocouple locations and data
acquisition system.

On the side wall of the fireplace, there are surface thermocouples directly underneath the combustible plywood touching the wall (zero clearance).

Start of test, 9:35 am

Brands are added every 7.5 minutes for 12 hours. Stack of brands
visible to the right of the clock.

see also:
additional description and data in Jim Buckley's Report