about which system is best suited for a
1. Perkins. Principles and Methods of
Sterilization in Health Sciences 2nd
Edition, Eight printing, 1983, P. 287
2. Block, Seymour Disinfection, Sterilization
and Preservation, Lippencott Williams
and Wilkins Fifth Edition
3. Waldrab, David, Hold the Steam,
November/December Issue ALN 2009,
4. Inactivation of Bacillus anthracis. Spores
Ellen A. Spotts Whitney, Mark E. Beatty,
Thomas H. Taylor, Jr., Robbin Weyant,
Jeremy Sobel, Matthew J. Arduino, and
David A. Ashford Emerging Infectious
Diseases • Vol. 9, No. 6, June 2003. P.
5. U.S. Energy Information Administration
(EIA). Electric Power Monthly with
Data for June 2017, Table 5. 6.A.
Average Price of Electricity to Ultimate
Customers by End-Use Sector, by State.
Marcel Dion is the director of marketing for Washing and Steam Sterilization
Systems in the Life Sciences Division
of STERIS Corporation. For the past
17 years, he has been responsible for
developing and introducing innovative
and efficient cleaning and sterilization
systems that are used in both research
and pharmaceutical applications.
Dave Karle has been offering consulting services in the field of steam
sterilization since his retirement from
STERIS Corporation in 2011. While
working for STERIS, Dave was Senior
Product Manager for 11 years, being
responsible for Steam Sterilizers used
in both Research and Pharmaceutical
Michael Palmer is a project manager/
engineer in the Life Sciences Division
of STERIS Corporation. For the past
18 years, he has been responsible for
managing projects for equipment that
are used in both research and pharmaceutical applications.
The installation of a dry heat sterilizer
is likely to be less expensive than that
of a steam autoclave. It usually does not
require a pit, it is lighter and easier to
install, and requires fewer utility services.
However, a larger dry heat sterilizer, or
even multiple dry heat sterilizers may
need to be considered to maintain the
same productivity as a steam autoclave.
Cost of Operation
The cost of operation is mainly composed
of utility and labor costs. There is no significant difference in the labor cost associated to the operation of the two types
At first glance, the utility cost for a
dry heat sterilizer should be lower than
that of an autoclave since the only utility
used is electricity and compressed air.
However, one must use caution since
the current cost of electricity ranges significantly from one region to another. A
recent report from US Energy Information
Administration indicates that cost of
electricity for the industrial sector may
Steam sterilizers require electricity, cold
water, and a steam source. Most research
or pharmaceutical manufacturing facilities
already have a source of steam in the
building that is readily available for use in
the autoclaves. Modern autoclaves can be
equipped with water and energy saving
systems that will drastically reduce the
consumption of utilities.
When comparing operation costs, it is
important to consider not only the cost of
the various utilities, but also factor in the
configuration and options that the sterilizers are equipped with as well as the
cycle parameters that will be used.
A dry heat sterilizer is likely to require
less maintenance due to its simplicity
relative to a steam autoclave. A dry heat
sterilizer is a non-pressurized vessel. It
relies only on an electrical heat source
and compressed air to assist in cooling
the chamber and the load items.
On the other hand, a steam sterilizer
requires a steam source, electricity,
water, and a drain. It is generally, but
not always, installed in a pit. A vacuum
system is sometimes required to evacuate
air and steam from the chamber during
Both steam and dry heat processes have
their limitations. Steam cannot be used
for processing any item that is unable to
tolerate moisture. With the dry heat process, there is no vacuum to draw the air
out of challenging areas of the load such
as tubing, canisters, peel pouches in the
pharmaceutical and research facilities or
cages and animal bedding in laboratory
animal research facilities.
Many products found in research facilities are made of polysulfone or polycarbonate. Some of these materials may not
be able to withstand the higher temperature required for dry heat sterilization.
Each sterilization process has its own
benefits and drawbacks.
Dry heat sterilizers are generally less
costly to procure, operate and maintain
than steam sterilizers, however, processing time may be as much as 2. 5
times greater than that of a steam sterilizer of the same capacity. Applications
for dry heat sterilizers are limited due
to the higher sterilization temperature,
the impossibility of processing liquids
and the absence of pressure/vacuum
Steam sterilizers provide more versatility as long as items to be sterilized
can withstand moisture, temperature,
pressure and in some cases, vacuum
conditions. They are likely to require
more maintenance, and in some cases,
may be costlier to procure and operate.
On the other hand, the productivity of
an autoclave is at least 2 to 2. 5 times
higher than that of a dry heat sterilizer,
providing shorter turn-around time and
potentially reducing the need for valuable
This information is provided to help
with making a well informed choice