GAS CALIBRATION ACCURACY VALUE

[francisco filipe domingos]

HELLO,
I buy a calibration gas from CK Gas Products Ltd, and the certificate of composition have this mixture accuracy +/-2%. This value is from repeatability or from reproducibility of some standard norm like ASTM, IP, OHSAS,etc..?
I send e-mail to the company, but didn't receive nothing yet.
Can someone help me, please?
Francisco

[MikeD]

Certificates from a calibration service accredited to ISO 17025 would have this information. CK Gas Products Ltd are not accredited to this standard, but even so their certificates should be more explanatory.

+/- 2% should refer to reproducibility, specifically, combined expanded uncertainty at 95% confidence. Only CK know for sure and they are not replying you say.

Write to them again quoting ISO 9001 7.2.3 Customer Communication
The organisation shall determine and implement effective arrangements for communicating with customers in relation to
a) product information;
b)enquiries, contracts or order handling...;
c) customer feedback, including customer complaints.

Having said all that and quoted the 9001 standard - CK Gas Products have chosen the registrar IMSM to certify their management system. The problem for me would be that no internationally recognised body has accredited IMSM to certify CK (eg. UKAS in the UK and A2LA, IAS, NVLAP, L-A-B or ACLASS in the USA). If I was in your position I could not normally accept the calibration certificate of CK without further enquiries, as you are doing.