NFPA 22 Tank Heaters

[KiwiMace]

Two questions:

1. Does the following clause mean that my 60'dia on-grade tank does not require a heater?

"15.2.2.1 Suction tanks, standpipes, and elevated tanks that have risers of 0.91 m (3 ft) or more in diameter shall not be required to have provision for heat."

2. If I still need a heater - Under NFPA 22, is it possible to use an immersion type electric tank heater? Code looks like a circulating unit is required - or alternatively can I gravity flow the bottom of the tank to the top through the heater?

Thanks in advance.
Glen

 

[trashcanman]

It depends on the local weather too. If the project is in Galveston, TX, I would say probably no heater required. If in Detroit, MI, I would think one is needed, even with that escape clause. Check the winter design temperature, and contact local authority. They will have to approve/disapprove it anyway.

 

[cdafd]

If I still need a heater - Under NFPA 22, is it possible to use an immersion type electric tank heater? Code looks like a circulating unit is required - or alternatively can I gravity flow the bottom of the tank to the top through the heater?

Which one do you fall unde???

If tanks are located where the lowest mean temperature for one day is less than -15°C (5°F),:

15.2.1.3 Immersed steam coils shall be used for suction tanks and standpipes that have flat bottoms supported near ground level in situations where the tank is kept filled so that the steam coils are continuously submerged.

Where the lowest mean temperature for one day is -15°C (5°F) or above,:

15.2.2.1 Suction tanks, standpipes, and elevated tanks that have risers of 0.91 m (3 ft) or more in diameter shall not be required to have provision for heat.



15.2.3 Where the lowest mean temperature for one day is above -9.4°C (15°F) as shown in Figure 15.1.4, the method of heating tanks with frostproof risers of less than 0.91 m (3 ft) in diameter shall be a steam loop or steam radiator, or thermostatically controlled electric strip heaters shall be placed inside the frostproof casing.

 

[MJCronin]

Cinci....

Anybody evaluate the cost of an electric tank heater ?

The financial/operating guys may get a little excited....

Is a "natural gas fired" tank heater a possibility for your installation ?

-MJC

 

[KiwiMace]

Thanks for pointing me to the temperature limit on that out-clause cdafd. I'm looking at -10degF, so stuck with it.

MJC - Electric is the only option here and with 3" of fibreglass, it isn't all that much to heat.

The water temp will only push below 42degF during shut downs anyway, with turn over every half day - shared use with process water keeps it flowing.