CHOOSING A LABORATORY AUTOCLAVE
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Priorclave Fact Sheet: Choosing an Autoclave.aec06/04/06 An informal Guide to Laboratory Autoclave Purchasing, with some advice and suggestions fromPriorclave Ltd. For many years the laboratory autoclave has been an essential item in any laboratory where microbiology workis carried out. However, spiralling amounts of justifiable but suffocating regulations over the last 25-30 years have changed the way they are specified, installed and used.All of this makes buying, specifying, installing and running a laboratoryautoclave more difficult than it used to be. Gone are the days when you could look through a catalogue to pick one out and once it was delivered, plug it in with a bucket behind to catch the drips, or a pipe running into the nearest drain or through the wall, set it to 15 minutes at 121 > o C and emptyit out again once there was no pressure inside.The addition of safety systems such as thermal or cooling locks, and theincreased requirement to ensure that the load is sterilised so as to meetvarious laboratory quality standards has extended cycle times dramatically.This has led to the development of accessories and systems becoming available on laboratory autoclaves toassist in optimising their performance for particular load types. Vacuum air removal, venting systems and accelerated cooling options are now more commonplace than before, and as in all walks of life, microprocessor control is everywhere.The vacuum and free-steaming systems fitted to manylaboratory autoclaves to improve performance, along with increasing concern about what is carried over in the exhaust steam from autoclaves, have also led to the formulation ofstandards and regulations, requiring most of them to beconnected to sealed and vented drains.Microprocessor control systems can be a nightmare to the technophobes amongst us, so it is important toconsiderwho is likely to be using the equipment and how often the settings may need to be changed. Some systems are as easy to set up as the timer and temperature gauges on olderђautoclaves, whereas others require a manual and passwords to make even a small adjustment to the set time or temperature. Both are equally valid but they must be applied in the right environment. For instance a level of security in setting the autoclave that is essential in a hospital or pharmaceutical production facility with fixed and validated cycles andwith non-technical operators, would be extremely frustrating to experienced laboratory scientists wishing to run a variety of sterilising cycles.It is also worthwhile taking into consideration the lifetime costs of the equipment when deciding what to buy.These would include factors such as electricity or steam used, the cost of water for cooling systems and vacuumpumps, if applicable, and also the cost of servicing and maintaining the autoclave. Generally speaking the morecomplex the equipment is the more maintenance and parts that will be required. As a general rule of thumb, themore moving parts the more things there are to go wrong, especially over the lifetime of the autoclave. In many cases it might pay to keep it simpleђas much as possible.As always when specifying or purchasing an expensive and complicated piece of equipment it is essential to beable to ask the right questions in order to get the right answers. It is important to think about what you are going to put into the autoclave to make sure that the autoclave that you buy has the right specification to process it effectively and efficiently, especially if you are going to have to prove this to a certifying body later on.The following questions and comparisons may help you in making your decision. They are not intended to give afull explanation of all the issues and technicalities but they should help you in narrowing down your choices a little. With this information you should at least be armed with some informed questions to ask of prospectivesuppliers and manufacturers. > Choosing a Laboratory Autoclave.docPage1 of 8www.priorclave.co.uk size="-1">

Priorclave Fact Sheet: Choosing an Autoclave.aec06/04/06 > + Faster chamber heat-up times as high temperature steam is instantly availableinside the autoclave + Because steam is injected into the chamber at pressure there is better circulationand penetration of steam than with electrically heated models. + Faster cooling than in chamberђelectrically heated models. There is no reservoir ofhot water in the bottom of the autoclave to be cooled down along with the load. - A reliable supply of dry steam is required. Some in-house supplies can be unreliable. An autoclave requires good quality...

Priorclave Fact Sheet: Choosing an Autoclave.aec06/04/06 - More expensive to run as the heaters will be operating all day to maintain the supplyof readily available steam. During a 10 hour day they will be running for 2-3 timeslonger than the heaters in a comparable electrically heated model and even longer if the generator is left running overnight. > Manual door withhandbolts- + Less complex, and so requires less servicing and is less expensive. - Requires opening space at the front and side of the autoclave. - Less convenient to open and close than single action or push-button operation....

Priorclave Fact Sheet: Choosing an Autoclave.aec06/04/06 Air Ballasting + For sealed or semi-rigid containers where very rapid cooling i.e. spray or waterjacket is used. Requires a supply of compressed air. Load / Performance qualification testing > Recording of cycle temperatures with multiple recording probes ensures that the autoclave settings will achieve sterilising conditions in all parts of the load. Afterinitial testing regular calibration of the autoclave is required to confirm the continued correct operation of the autoclave. > Testing requires specialist staff and equipment can...

Priorclave Fact Sheet: Choosing an Autoclave.aec06/04/06 > No longer common with the advent of more reliable temperature systems. Can leadto under-temperature cycles if air remains in the autoclave Temperature and Time > Ensures adequate temperature sterilising conditions if air remains in the autoclave. Other Methods With the sophisticated microprocessor controls now available an alternative system for controlling sterilisation hasbeen devised, known as F0 .F0 is a lethality calculation used extensively in Food Processing and in Pharmaceuticalapplications. It takes into account the time...