Rank: Forum user 
|
Dear all
I have been asked to advise on whether our PAT tester should, whilst he's at it, check our microwaves for 'microwave leakage' - they are in varying uses within large senior schools, some used by staff, some by pupils. I know nothing about this, never heard of it before and hence I'm a little loathe to say yes or no. Does anybody have any guidance on this or do you purchase it and if so, why (or why not!)
|
|
|
|
|
|
Rank: Super forum user
|
Are you using a contractor to undertake the PAT testing?
If so you should speak to them to see if they have the training & testing equipment to undertake?
|
|
|
|
|
|
Rank: Forum user
|
The advice I've reaad (sorry no reference available) usually says that provided the microwave is in good condition, clean and the door seals remain effective, then leakage of radiation is minimal.
Assuming this is a domestic kitchen sized microwave in a rest room etc then, if the oven gives cause for concern regarding condition - it will be just as easy to replace it with a new one. (est £100 max)
Measuring microwave radiation is just another 'add on' over the top task advised by PAT people etc, looking to generate extra income.
|
|
|
|
|
|
Rank: Guest
|
Is this another 'PAT' myth.
We had a manager with a 'pen' detector' years ago that did this and I know you can get these for less than £15, there then a 'meter' type at anything from £25-300.
We then had two of hours done (tagged on to the PAT) and I was horrified when we were charged £10 each which seems a rip off! not be falling for that one again.
HSE guidance (what I could find) focuses on the door assembly, seal and interlock, all of which I think could be done in house with the right equipment. If there alot of appliances this may be cost effective. Happy to be proved wrong by the electrical gurus as I still need to plan how to tackle it later this year.
|
|
|
|
|
|
Rank: Super forum user 
|
In the early days of microwave ovens, EHOs would come out and check for leakage.
As has already been stated, provided the seals are clean and in good repair there should be no issue.
The small leakage indicators which usually have an LED which lights up when leakage is detected have to be used with care. They will invariably indicate some leakage if used on an empty oven - a small cup of water must always be placed in the oven.
That is my sum knowledge on the subject and as others have intimated, this (cynically) is a money making exercise.
|
|
|
|
|
|
Rank: Super forum user
|
A lot will depend on the size and power of the oven - the manufacturers operating instructions will highlight the maintenance requirements and MAY include leakage testing as part of routine maintenance. But NOT as part of PA testing as I believe this is just a money making exercise. See link which may help. http://www.cesa.org.uk/u...ding_microwave_ovens.asp
|
|
|
|
|
|
Rank: Super forum user
|
There is an example of an EMF risk assessment of using a Microwave oven In HSE Operational Circular OC 497/1 on page 9 in Appendix 1 at:- http://www.hse.gov.uk/fo...fod/oc/400-499/497_1.pdfIt identifies that provided the oven housing is undamaged, door seals are in good condition, interlocks are working, no emission measurement is necessary as the Risk is LOW. The control measures are daily cleaning to prevent build up of spillages, regular functional check of interlocks, routine inspection for damage to housing
|
|
|
|
|
|
Rank: Super forum user 
|
I think that this is one of the issues with "PAT" as a regime.
There is another linked thread running at the moment along these lines.
The IET (IEE) publish a CoP for "In Service Inspection & Testing of Electrical Equipment" this is currently in its 3rd edition.
This is the document upon which the C&G qualifications in "PAT" are based.
This document is referenced in HSE guidance.
The problem is that most believe that "PAT" consists of a combined inspection & test by a competent person, at the intervals given in IET & HSE guidance.
This is incorrect.
The document along side me lists 3 kinds of checks / tests all of which go to fulfil the "PAT" requirement.
User checks, basic safety inspection prior to use of equipment.
Formal visual checks.
Combined inspection & test (AKA "PAT").
One cannot function without the others to meet the IET CoP.
The issue with the microwaves is that the IET document now "requires" that the function of the door interlock is checked, easy if you know how!
Also that leakage should be checked at appropriate intervals.
This has been taken as an annual check by some, in the same way that it is taken that all equipment in offices etc. requires at least an annual "PAT" which is rubbish.
Just because it has a BS1363 or BS EN 60309 plug on it does NOT mean it has to be subject to "PAT" at least every 12 months!
There is a little phrase often used on here, "Risk Assessment".
Annual "PAT" is not sufficient on its own, and in itself is an overkill in certain circumstances.
The most important but most overlooked requirement is for user checks and encouragement to identify and report possibly defective equipment.
|
|
|
|
|
|
Rank: Forum user
|
In the past I sometimes carried out repairs on commercial microwave ovens, (and other commercial catering and laundry equipment). I used to test microwave ovens for leakage (before and after the repair. I did find some commercial ones had a problem, not a lot, but yes some did leak. I found the cause was often the door interlock, the oven would work but the door was not fully closed, there was a very slight gap , and would leak around the door area. The wear in the interlock was obvious, and this wear was often as a result of the door hinges dropping a little. Normally wear in the door interlocks would result in the oven not working. Some ovens have several interlock switches, but one brand had an interlock unit, composed of several internal switches. They usually are designed if the interlock fails, the main appliance fuse fails.
I never found a domestic microwave oven leaking, and i did work on several. Now when domestic ovens fail, it is a recycle job.
If microwave ovens are ever repaired I would insist they are checked for leakage by the repair person, if they do not have the test meter, get another repair person/firm.
|
|
|
|
|
|
Rank: Guest
|
A while ago (at least 20 years) a lot of organisations (especially public sector) introduced leakage testing using cheap 'micky mouse' testers. Also Environmental Health Departments often offered a service (possibly to other public sector work places but my memory is a bit hazy) using much more sophisticated calibrated meters. Then HSE published one of their old guidance sheets (Plant series/catering series??)saying it was unnecessary to test (but just visually check the seals). They also said the micky mouse testers were not accurate. I've just found this SIM (dated 2009) which includes as an example 'Microwave oven EMF risk assessment'. It says, 'no emission measurement is necessary: Risk is LOW.' http://www.hse.gov.uk/fo...fod/oc/400-499/497_1.pdf
|
|
|
|
|
|
Rank: Forum user
|
Many thanks for your replies everyone - very helpful indeed.
|
|
|
|
|
|
Rank: Guest
|
Sorry Jay; I missed your posting.
|
|
|
|
|
|
Rank: Forum user
|
When the university I worked in, before I retired, introduced microwave ovens in student kitchens they was an understandable concern regarding emissions
So we did carry out emission testing at the same time as we carried out electrical testing. We did use a calibrated instrument.
This I might add was before the introducion of PAT testing.
After several years it was apparent that the only time emissions could be detected was if there was any apparent damage to the door or the seals
By this time we had over 500 microwaves in use, it was closer to 1000 before I retired
The decision was there for taken to discontinue emission testing and simply to train the domestic staff to report and damage to the units.
Electrical testing did of course continue.
|
|
|
|
|
|
Rank: Forum user
|
Opps made a typo
The last but one para should read
The decision was therefore taken to discontinue emission testing and simply to train the domestic staff to report ANY damage to the units.
Wish we had an edit for the forum posts
|
|
|
|
|
|
Rank: Guest
|
I thought you were training them to hit the microwaves with a hammer or something!!
|
|
|
|
|
|
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.