PHD Group Ltd.
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  Frequently Asked Questions - (FAQ)      
  1. What exactly does 'explosion-proof' mean?
  2. How long will my 150 lbs. tank last?
  3. How does a PHD Heater compare to a diesel heater?
  4. Why does your heater use propane instead of diesel?
  5. Where can I fill my propane tank?
  6. Can you be reached 24-hours a day in case of emergency?
  1. What exactly does 'explosion-proof' mean?

The intrinsically safe and explosion-proof PHD Load Heater is manufactured to the Military Standards of Canada and the U.S.A., and is certified by the Canadian Explosive Atmosphere Laboratory for use in the transportation of dangerous goods. For a full account of our certifications and standards, follow this link.

The PHD Heater activates and runs without any flame or spark. There is no risk of fire or of explosion when exposed to flammable gases, which makes this mode of heating ideal in areas classified as dangerous.

Furthermore, papers or materials (such as nylon) placed accidentally or on purpose in contact with the PHD Heater will calcine and sublimate without a flame.

One final intrinisical safety mechanism is a revolutionary two-stage process that controls the flow of propane during activation. During start-up, a lowered propane output is supplied to the catalyst to ensure complete activation without releasing unburned propane . After full catalyst activation, the main propane flow is activated, providing up to 30,000 BTU/h.

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2. How long will my 150 lbs. tank last?


The PHD Load Heater is rated and tested to keep your trailer at 65oF for 200 hours with an outside temperature of -40oF (some customers boast up to 400 hours under normal use).

This rating is based on a standard length trailer (approx. 53' x 9' x 9'). Gas consumption will vary depending on several factors, including but not exclusive to trailer insulation, trailer size, initial trailer temperature, outdoor temperature, thermostat setting, volume and type of loads (optimally, place loads on wooden skids to allow for greater air circulation).

The PHD Heater is 100% efficient rating in its destruction of propane into heat energy, requiring 0.4 litres of propane per hour. This is exceptional when compared to diesel fuel requirements at 1.32 litres per hour (sealed flame combustion has a 50% efficiency rating).

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3. How does a PHD Heater compare to a diesel heater?


When presented with all the facts, there truly is no comparison. Take a minute and the opportunity to introduce yourself to the differences in our comparison section, and find out for yourself.

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4. Why does your heater use propane instead of diesel?


We chose to develop a propane heating system (first introduced in 1967) for 6 main reasons:

1. Propane is non-toxic

Propane is not harmful to soil or water. Because propane does not endanger the environment, the placement of propane tanks either above or below ground is not regulated by the Environemtnal Protection Agency (EPA).(1)

NIOSH recommends that whole diesel engine exhaust be regarded as a potential occupational carcinogen. Follow OSHA and NSHA rules where diesel engine exhaust fumes may be generated.(4)

2. Direct firing without alternation or discoloration (2)

There is no contamination of fume problems with unburnt fuels.(2) If a propane leak should occur, the trailer cargo will remain safe and completely unharmed, with no thick and heavy odour, taste, or stains.

Furthermore, this direct, one-step clean-burning heat transfer is lead free, sulphur free and carbon monoxide free.

3. Propane has a narrow range of flammability (3)

"Propane has a narrow range of flammability when compared with other petroleum products and has the lowest flammability range of any fossil fuel. In order to ignite, the propane/air mix must contain from 2.2 percent to 9.6 percent propane vapor. If the mixture contains less than 2.2 percent gas, it is too lean to burn. If it contains more than 9.6 percent, it is too rich to burn."(3)

Furthermore, "Propane won't ignite when combined with air unless the source of ignition reaches at least 940 degrees Fahrenheit. In contrast, gasoline will ignite when the source of ignition reaches only 430 to 500 degrees Fahrenheit."(1)

4. If propane leaks, it dissipates (3)

This is true with both liquid and gas forms.
If liquid propane leaks, it doesn't puddle but instead vaporizes and dissipates into the air.

5. Propane has a lower freezing/pouring point than diesel.

The freezing points of propane and diesel are approximately -188oC (-306oF) and -44oC (-48oF). More importantly, diesel fuel's "pouring point" is closer to -30oC (-22oF depending on additives/quality). This limitation, depending on the weather, fuel quality, and battery, with the additional need to 'crank' the engine, may prevent your diesel heater from starting.(4),(5)

PHD load heaters run on propane and contain no moving parts to 'crank'. Our choice of fuel and design is dependable no matter what the conditions are.

6. Propane is safe and convenient

"Propane tanks are constructed from carbon steel under a code developed by the American Society of Mechanical Engineers. A propane tank is 20 times more puncture resistant than a typical gasoline, methanol or ethanol tank." (6)

Propane availability is growing due to it's demand. Currently, there are over 20,000 propane fueling stations in North America; you can find one conveniently through the following links.

    1. Locate a propane station anywhere in the U.S.A.
    2. A route mapper with propane stations listed
    3. Superior Propane near you (Canada)
    4. Most Flying J locations supply propane

In conclusion, by using propane gas instead of diesel or electricity, we found that our customers can cut emissions and costs while increasing reliability and safety.

(1) National Propane Gas Association (
(2) Giri Energy (
(3) Propane Education and Research Council (
(4) Diesel Material Safety Data Sheet (MSDS)
(5) Propane Material Safety Data Sheet (MSDS)
(6) National Propane Gas Association (

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  6. Can you be reached 24-hours a day in case of emergency?  

Yes. We can be reached 24-hours a day / 7 days a week at: 416-670-3651, ask for Derek.

During business hours, M-F, 8am-5pm, please call 905-855-9600 (toll free: 1-800-220-5513) for any questions or concerns you may have.

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Copyright 2004 by Protective Heat Development Group Ltd.

Protective Heat Development Group Ltd.
2568 Royal Windsor Drive, Mississauga, Ontario, L5J 1K7 - 1-800-220-5513