What is Double Filtered Air?

For Meridiano 87, the double air filtering air is one that not only meets international standards to be certified as Grade E (Haz Clic aquí para conocer ¿Qué es Aire Grado E?) if not, makes a further filtering process that can be used on rolls ready for use with gases with a high content of oxygen. This is also known by its English acronym OCA or Oxygen Compatible Air. In the case of meridian double air filter 87 additionally meets the regulations for air USP Medical Grade.

The Filtered differs mostly outdoor grade E for its extremely low level of oil pollution as shown in the tables below


Pollutant M87 Filtered Air Allowable O.C.A Allowable U.S.P
Carbon dioxide < 500 ppm 1000ppm 500ppm
Carbon Monoxide < 1 ppm 2 ppm <10ppm
Total hydrocarbons < 1 ppm 25 ppm 5ppm
Water vapor < 3 ppm 67 ppm 10ppm
Wet Bulb Temperature (F) -65 F -50 F NA
Oil mg/cm3 < 0.1 mg/cm3 0.2 mg/cm3 NA
Particles mg/m3 < 0.1 mg/m3 0.1 mg/m3 NA
Smell Not detectable Not Detectable Not Detectable
Nitrous oxide (NO+NOx) Not detectable NA Not Detectable
Sulfur dioxide(SO2) Not detectable NA < 5 ppm

Pollutant Aire M87 Allowable (Grado E)
Carbon dioxide < 700 ppm 1000ppm
Carbon Monoxide < 1 ppm 10 ppm
Total hydrocarbons < 1 ppm 25 ppm
Water vapor < 28 ppm 67 ppm
Wet Bulb Temperature (F) -65 F -50 F
Oil mg/cm3 < 1 mg/cm3 5 mg/cm3
Particles mg/m3 < 1 mg/cm3 5 mg/m3
Smell Not detectable Not Detectable