What is the most important precaution
that I should take once I have activated the heater?
- The heat generated is felt in a
few seconds and steam will be seen. Do not
burn yourself. Once the heater has been
activated, place it immediately on the
polystyrene plate and then back into the box.
This will insulate the meal and help the heater
to work more efficiently.
How does the heater work?
- When water is added to the heater
sleeve, it reacts with a mixture of magnesium
iron alloy and sodium chloride (FDA approved food
grade additives). This generates heat and steam
and is scientifically known as an exothermic
Is the chemical reaction safe?
- Yes! The only caution is to
avoid spilling the hot water that is inside the
heater sleeve or holding the heater sleeve
immediately after activation because both are
- An activated heater produces heat
and steam. The chemical end product is magnesium
hydroxide. This is a common antacid
frequently prescribed by doctors.
If the end product is an antacid,
does this mean the product could be ingested without
No! The heater and its
by-products are not for human consumption.
Is the heat reaction similar to the
small pouches that we buy to keep our hands warm?
No! The reaction is more
intense and reaches very high temperatures (up to
83°C or 178°F) in only a few minutes. The heat
is maintained for about 30 to 35 minutes. After
that it gradually cools down.
Once I have activated the heater by
adding the water to the sleeve, do I close the sleeve to
obtain better heat?
No! Fold the heater sleeve
once as shown on the instructions. Do not attempt
to reseal the heater sleeve. The steam must be
allowed to escape.
The heater sleeve was accidentally
pierced. Can I still use it?
No! You should not use the
heater but you must carefully activate it with
water before discarding. Be aware that activating
it generates heat and steam.
Is this technology being used
Yes. The technology was
first introduced during DESERT STORM
(1992) to heat the US military meals known as
MREs. In 1998, 28 million heater sleeves were
used by the US military.
Since 1997, the military (MoD) in
the United Kingdom began purchasing heaters and
in early 1998, the Canadian military purchased a
quantity for trial purposes.
I have seen a similar heater before
when I was in the American military. Are these the same?
If you were in the American
military before 1996, then the answer is no. The
present heater is a more advanced version of the
first heaters introduced during Desert Storm.
In 1991, the heater device was a solid, cindered
pad in a very narrow bag. Since 1996, the new
design is lighter, more flexible, takes less
water to activate and generates more heat. It is
made up of granules of Magnesium coated
with Sodium Chloride and incorporated in a
semi-permeable membrane and inserted in a wider
How hot does the food get?
- If the food is kept at normal room
temperature and heated with the heater, the food
should reach 80°C or 178°F in approximately 12
If we refer to the
performance data sheet, we will note that 300 g of water
will reach the following temperature:
12 minutes using the heater
|4°C or 44°F
||76°C or 168°F
|28°C or 84°F
||83°C or 178°F
point = 0°C or 32°F Boiling point = 100°C
How long will the heat last?
- The heater will generate heat for
approximately 35 to 40 minutes depending on the
Can I use the heater for other
purposes after the meal has been heated up?
- The heater will keep its heat for
some time and can be used for body warmth. Care
should be taken if there is any water inside for
it might leak out and burn you.
- Normally, fifteen (15) minutes
after the heater has been activated, the water
has been absorbed by the heater itself or has
evaporated as steam and only dry heat is left.
- There is enough heat left after 12
minutes to warm up a cup of liquid.
Can I use the heater to heat water
for a hot drink?
The heater was originally designed
to heat the meal pouches. However, it can be used
to heat up water for a hot drink as well. The
ideal method is to use a ½ liter Platypus or a
ziplock bag filled with approximately 1 cup of
your choice of liquid (water, milk, etc.). If
used with a new heater, 300 g of liquid will be
at 83°C or 178°F in approximately 12 minutes.
What else could the heater be used
In winter, for survival
conditions, water may be difficult to find. Take
a quantity of snow, place in a large plastic bag.
Activate the heater and place under the bag of
snow allowing the heater to vent the steam. The
snow will be melted.
Can the heater be used more than
The answer should be no but we
have noticed that on numerous occasions, the
water has not infiltrated into all the heating
elements inside the membrane. By adding
approximately 1 tablespoon of water after 35
minutes, the heater can be reactivated. This heat
is great to warm yourself with or to warm a
Is it safe to put the heater in a
After use, dispose of all the
elements of HOT
PACK® whether it
be the aluminum food pouch or the heater or the
heater sleeve as you would any other refuse.
Is the heater and the heater sleeve
Yes! Both the heater and
heater sleeve are recyclable but they are not
If I do not use the heater because I
did not need it, can I just throw it out?
The heater can be used at any time
and is safe to keep sealed in the sleeve.
However, always activate the heater with water
Can the heater be used to heat the
food pouch if it is frozen?
The heater was not designed
to heat food from frozen but will effectively
defrost and warm it through in about 30 minutes.
If you want a meal at 83°C or 178°F, a second
heater must be used.
Can I use ordinary water to activate
the heater or is the water in the sachet specially
The activating sachet contains
ordinary tap water. The important thing is not to
over-saturate the heater with water. The sachet
contains 40 ml (1.5 oz.) of water. If you use
other water add only to the fill line as shown on
If I am in a sailboat and want to
use salt water, will that work?
Yes! Any liquid would
activate the heater.
Are there any toxic elements to the
heater or heater sleeve?
No! Not to our knowledge.
Must the heaters be stored in a
The heaters should be kept in an
area that is dry and away from open flames. The
temperature of the room is not important.
Are you saying that the heater could
be stored in a cottage that has no heat and therefore
very cold? Would it still work?
The heater is not affected by
Can the heaters be affected by
humidity in a room?
No. The heaters are in a
sealed sleeve. However, the heater sleeves should
be kept away from any contact with water.
If the sleeve is damaged then you
must activate the heater with water and dispose
of the heater/heater sleeve. Care must be taken
because of the steam and heat being generated
when the heater is activated.
If you open the heater sleeve and
decide not to use it immediately, humidity can
get in and the heater might not function to its
full capacity. It is considered inadvisable to
open the sealed sleeve and not use it
How many heaters can be activated at
one time if we are in a confined space such as in the
cabin of a truck (6' x 6') or in a mine shaft?
The main consideration is not the
size of the space but ventilation. A minute
amount of hydrogen is given off. This displaces
oxygen. That is why we say "Activate the
heater in a well-ventilated area". There
are, however, no toxic fumes.
What is the sweet smell that we
detect when we activate the heater?
The smell is magnesium being
activated and is in no way toxic. All the
ingredients in the heaters are FDA food grade
How much hydrogen is given off?
A trace amount mixed with steam.
An hypothetical situation:
"There are 15 men inside the cabin of a fire truck.
It is winter and the doors are shut to keep in the heat.
How many heaters can be activated at one time?"
Make sure there is plenty of
ventilation. By doing this, there is no problem
in activating 15 meals (one for each of the men).
Always activate the heaters in a ventilated area.
The meal did not seem to get really
hot after 12 minutes. Why?
Make sure the heater is placed UNDER
the meal before activating with water. If the
heater is on top of the meal, the water will not
make contact with the heater and therefore no
heat will be generated.
Equally, if during meal insertion,
the heater has been bunched up at the bottom of
the sleeve, it will not work as efficiently. MAKE
SURE THE HEATER STAYS FLAT UNDER THE WHOLE MEAL
It is also possible that the
heater and meal inside the sleeve were not kept
reasonably flat initially (first 30 seconds). The
heater needs to absorb the water through each
membrane and heater element to obtain maximum
Is the heater affected by altitude?
No! In October 1997, a
climber from Vancouver, British Columbia
activated the heater at 25,350 feet on Mount
Everest. He was delighted to note that it was not
affected by the elements. As you are aware, it is
extremely difficult to light a fire or stove at
high altitudes because oxygen is required. This
is not so for the heater. Sadly, the team had to
return to base camp because the weather was
ferocious. No one made it to the top!
With normal cooking stoves, cooking
time doubles every 5000 ft of elevation gain. How does
PACK® heater compare
- The HOT PACK® heater does not rely on oxygen
in its heat process. The Magnesium &
Sodium Chloride mixture works at any altitude
once water has been added.