Hi Derek, we sent a tech bulletin on this recently and dare I say it almost suggested people use common sense! I’d also like to see a field blank associated with each certificate (with the exception of personals) just so its easier when UKAS want to see evidence of a FB associated with each job. Here’s our bulletin, its will be a little more formalised in the SOP but might be useful for you to know our thoughts:
Here we are again…every certificate should have a field blank associated with it.
Remember the purpose of a field blank is to rule out contamination in the set-up process of a sample up to the point just before air is drawn across the filter.
The field blank is taken to the sampling area where you are placing your pumps, the cap is removed and replaced after a few seconds.
It is ok to collect multiple field blanks – for example you may conduct a batch of tests in the morning and then some more in the afternoon. I would argue two should be conducted here while conditions could be different am to pm even if sampling in the same location.
Conducting leaks and then a CoR in the afternoon – two field blanks needed here you are sampling the air in two different locations.
Think about what you are trying to rule out and if conditions in terms of time or environment change then do another. The wording in the SOP will be changed to reflect this in future.
We don’t want to see any certs that don’t have a field blank. PLEASE 🙂
