Construction

Question 1

Heating and power boiler clearances?

Answer 1

With manhole 84”

Without manhole 36”

Question 2

Power boiler clearance?

Answer 2

36”

Question 3

Boilers bottom open clearance, how much clearance?

Answer 3

12”

Question 4

When does an electric boiler require 2 blow down?

Answer 4

When the nominal water content exceeds 100 gallons

Question 5

What is the minimum size of a heating boiler blow down?

Answer 5

3/4” is the minimum. But…

If the capacity does not exceed 25 gallons 3/4”

Exceeding 25 gallons - falls under table 3.7.7.2 and is based on min required safety valve capacity.

Up to 500 - 3/4"
501-1,250 - 1
1251-2500 - 1 1/4
2501-6000 & 1 1/2
6001+ - 2

Question 6

Power boiler min feed water piping size

Answer 6

1/2” up to 100 sq ft

3/4” greater than 100 SQ ft

Question 7

Minimum and max safety relief valve size for a steam heating boiler?
What about HWH, HWS, and potable hot water heaters?

Answer 7

Steam - 1/2” to 4”
HW H/S greater than 15,000 BTU/hr - 3/4” to 4”
HW H/S up to 15,000 BTU/hr - should be 1/2”
Potable water heaters - T&P at least 3”