An enquirer asked today:
>> A supplier has said that they are not going to use ESD coats but use a
>> standard poly cotton coats and this was acceptable. I believe this is
>> not correct please can you confirm that they should be using esd type
This is an interesting question and really subject to personal judgement of the facility ESD Coordinator.
61340-5-1 includes garments under "ESD Protective items" and says "Specific ESD protective items when used within an EPA shall have the characteristics described......measured in accordance with the test methods.... at the highest and lowest expected or rated humidity values".
In other words you don't have to use ESD protective garments, but if you do use them they must comply with the specifications given. The specifications include:
"Coats, jackets, smocks and overalls shall completely cover all clothing in the area of the arms and torso"
"There shall be electrical continuity between all parts of the garment."
Garments shall characteristics on the outward facing surface in accordance with table 1"
"Garments complying with ESD requirements shall be clearly marked" (with the appropriate ESD symbol recommended)
Table 1 merely says that the point-to-point resistance (Rp) must be less than 10^12 ohms. In addition, a charge decay test is mandatory where Rp > 10^10 ohms or the "material is of non-homogenous woven or other construction containing insulating areas"
So, providing any coat supplied for use in the EPA has Rp < 10^10 ohms over there range of expected or rated operating humidities, it is compliant with the standard. If it has 10^10 ohm < Rp < 10^12 ohm, it should probably also have to pass the charge decay test. In practice many perfectly good ESD coats will fail the charge decay test, and it is planned to be omitted from the next version of the standard! Pragmatically I normally advise users if necessary to waive this last requirement, making note of the technical reasons for doing so.
So in short, if your suppliers coats meet the Rp < 10^12 ohm criterion (especially at low humidities) I would probably accept this as compliance with 61340-5-1.