Electric radiant heat in fire stations apparatus bay floor

[TheCommish]

2012 IECC, Massachusetts, less than 20k SF building, apparatus bay 80x60 feet, primary HVAC for the area eclectic heat pumps, with secondary electric resistance heating elements in the slab.

Primary heating system accounted for in COMcheck, no entry for electric resistance heating in the calculations.

Reading IECC, exterior ice melt systems cover in the code. My reading of the IECC does not uncover except for C402.2.6 Insulation of Radiant Heating Systems any performance requirement for the slab system.

My reasoning is that it is a heating system and should be carried in the calculations for the total building energy performance.

any comments or guidance?

 

[Yankee Chronicler]

I agree. And the presence of radiant heating in the floor slab also affects the extent and R-value of the under-slab insulation.

It's not a question of performance requirements for a radiant heating system. The IECC requires that the building meet energy performance requirements. Obviously, the radiant system has to be factored into the COMcheck. If the engineers didn't think it will be needed to maintain interior climate, they wouldn't have included it in the design. Since it's included in the design, it has to be included in the calculations.

You wrote: "... primary HVAC for the area eclectic heat pumps, with secondary electric resistance heating elements in the slab."

Does this mean they omitted just the radiant slab system or that they also failed to account for the electric resistance heating in the heat pumps? Or do these heat pumps not have built-in resistance heating elements, because the radiant floor slab fulfills the function of taking over when the heat pumps can't generate enough heat"

In reality, COMcheck may not be sophisticated enough to be able to handle a system of heat pumps plus radiant floors. The engineers may need to resort to more sophisticated energy modeling software.

 

[TheCommish]

The heat pumps are air source high efficiency units with refrigerant sets to the air handlers that service the apparatus bay. The electric heat in the slab is to supplement the bay heat, as the vehicles enter and leave the building is my understating,. Possibly to help offset the cold soaking of the apparatus as they may spend long periods of time outside in cold weather.

 

[e hilton]

Also to melt snow and water that gets carried into the building.

 

[steveray]

The heat pumps are air source high efficiency units with refrigerant sets to the air handlers that service the apparatus bay. The electric heat in the slab is to supplement the bay heat, as the vehicles enter and leave the building is my understating,. Possibly to help offset the cold soaking of the apparatus as they may spend long periods of time outside in cold weather.

If it is installed to serve the loads of the building Shirley it should be in the load calcs....?

 

[TheCommish]

I think it should be included and have been trying to drag the correct answers out of the designer with the usual changes, working on the according to sections xxxx you need to include the energy usage. At this point I am lining up my code path because RDP doesn't get the show me how this meets the code as present questions

 

[steveray]

Thank God we are not going to have to worry much about electric resistance in houses come 2024 code.... Heat pump folks took care of that for us...

R403.7.1​

Detached one- and two-family dwellings and townhouses in Climate Zones 4 through 8 using electric-resistance space heating shall limit the total installed heating capacity of all electric-resistance space heating serving the dwelling unit to not more than 2.0 kW or shall install a heat pump in the largest space that is not used as a bedroom.

 

[Yankee Chronicler]

Thank God we are not going to have to worry much about electric resistance in houses come 2024 code.... Heat pump folks took care of that for us...

R403.7.1​

Detached one- and two-family dwellings and townhouses in Climate Zones 4 through 8 using electric-resistance space heating shall limit the total installed heating capacity of all electric-resistance space heating serving the dwelling unit to not more than 2.0 kW or shall install a heat pump in the largest space that is not used as a bedroom.

So if I put a heat pump to serve the living room I can then install 5kW of electric resistance heat?

That's what it says ...

 

[steveray]

So if I put a heat pump to serve the living room I can then install 5kW of electric resistance heat?

That's what it says ...

Kind of….#energypeopledontknowhowtowritecode