Subatmospheric Gas Delivery System : A cylinder containing an electronic gas absorbed on a medium (zeolite or activated carbon); the gas is maintained at less than one atmosphere pressure (760 torr)
NFPA 318 Standard for the Protection of Semiconductor Fabrication Facilities, 2002 ed. http://www.nfpa.org/assets/files/AboutTheCodes/318 /Errata318-02-2.PDF, (Std: Prot of Semiconductor Fabrication Fcilty - Amer) {297 NFC}