Air care

C and R Testing can help with your air-care needs.

The information below gives the maximum allowable levels of contamination. 


Maximum allowable to BS EN12021

Oxygen content

(21 ±1)% by volume (dry air).

Carbon Monoxide content

Shall be as low as possible but not exceed 5 ml.m-3 (5 ppm).

Carbon Dioxide content

Shall not exceed 500 ml.m-3 (500 ppm).

Lubricant content (droplets or mist)

Shall not exceed 0.5 mg.m-3.


There shall be no free liquid water. The maximum water content of the air measured at:

  • compressor system outlet for filling cylinders, should not exceed 25 mg.m-3;
  • a cylinder outlet, cylinder pressure from 40 to 200 bar, should not exceed 50 mg.m-3;
  • a cylinder outlet, cylinder pressure >200 bar, should not exceed 35 mg.m-3.

Other Contaminants


Odour and Taste

The air shall be without significant odour or taste.


No dust, dirt, metallic particles, toxic or iirritating ingredients

About Company

C & R Testing Ltd has been established for more than 20 years engaged in electrical installations and servicing, compressor maintenance, installation, air purity testing, cylinder testing and oxygen cleaning.

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Get in Touch

  • Alkin UK phone:
    01422 410466
  • C&R testing phone:
    01422 557707
  • Email:
  • Address:
    Unit 1 Owenshaw Mills
    Sowerby Bridge
    HX6 2AF