Download - Hazardous Area Trace Heating
What is an explosive atmosphere?
An explosive atmosphere location is defined as a place
where concentrations of flammable gases, vapors, or
dusts occur. If there is enough of the substance, mixed
with air, any source of ignition could cause an explosion.
Explosions could lead to loss of life and serious injuries
as well as significant damage and expense. Preventing
the concentrations of dangerous substances, which
create an explosive atmosphere, and preventing the
ignition source are the two most commonly used ways to
reducing the risk.
All electrical equipment that must be installed in hazardous
locations are specifically designed and tested to ensure it does
not initiate an explosion, due to arcing contacts or high surface
temperature of equipment.
What is a stabilised design?
A stabilised system is where the power loading of the trace heating tape is such that under conditions of no
temperature control i.e. thermostat failure, the sheath temperature of the tape cannot exceed the ‘T’
classification.
Ideally all heat trace systems should be designed to be stabilised systems.
Where stabilised designs cannot be achieved it is
necessary to employ an over-ride thermostat with
lockout and alarm facility to prevent the ‘T’
classification being exceeded.
NOTE: non-stabilised designs may lead to
operational problems as the over-ride thermostat
may prevent the electric trace heating system
delivering the required heat output (kWhr) under
low ambient temperature conditions. It is therefore
essential that the thermal design characteristics of
the system are carefully evaluated.
Hazardous areas…
* Zone 0 * An area or enclosed space within any
flammable or explosive substance, whether as, vapour,
or volatile liquid, is continuously present in
concentrations within the lower and upper limit
flammability.
* Zone 1 * An area in which any flammable or explosive
substance, whether gas, vapour or volatile liquid, is
processed, handled, or stored, and is likely to occur in
sufficient quantities to produce a hazard.
* Zone 2 * An area in which any flammable or explosive
substance, whether gas, vapour or volatile liquid
although processed or stored, is so well under conditions
of control that the production or release of an explosive
or ignitable concentrate in sufficient quantity to constitute
a hazard is only likely under abnormal conditions.
As an ATEX Certified Company, ESH Trace Heating Ltd hold approvals for the manufacture and installation of explosive atmosphere trace heating solutions.