The purpose of this Subpart is to ensure that gas metering that could affect a customer's bill is accurate. This Subpart applies to all custody transfer meters and all meters that measure the gas usage associated with utility-owned equipment including usage by pipeline heaters, compressors, fuel gas, and storage field injections and withdrawals whose readings directly or indirectly affect a customer's gas utility bills. This Subpart does not apply to sub-metering that will not affect a customer's gas utility bills.
Ill. Admin. Code tit. 83, § 501.100