{"data":{"id":"us/40-cfr-1065.290","jurisdiction":"us","citation":"40 CFR 1065.290","heading":"PM gravimetric balance.","body":"(a) Application. Use a balance to weigh net PM on a sample medium for laboratory testing.\n(b) Component requirements. We recommend that you use a balance that meets the specifications in Table 1 of § 1065.205. Note that your balance-based system must meet the linearity verification in § 1065.307. If the balance uses internal calibration weights for routine spanning and the weights do not meet the specifications in § 1065.790, the weights must be verified independently with external calibration weights meeting the requirements of § 1065.790. While you may also use an inertial balance to measure PM, as described in § 1065.295, use a reference procedure based on a gravimetric balance for comparison with any proposed alternate measurement procedure under § 1065.10.\n(c) Pan design. We recommend that you use a balance pan designed to minimize corner loading of the balance, as follows:\n(1) Use a pan that centers the PM sample media (such as a filter) on the weighing pan. For example, use a pan in the shape of a cross that has upswept tips that center the PM sample media on the pan.\n(2) Use a pan that positions the PM sample as low as possible.\n(d) Balance configuration. Configure the balance for optimum settling time and stability at your location.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER U—AIR POLLUTION CONTROLS","PART 1065—ENGINE-TESTING PROCEDURES","Subpart C—Measurement Instruments"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"774421a46be083e167814693a90e40aa1c1f950219dc3b5f974b3e1939da25c1","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1065.284","next":"us/40-cfr-1065.295"},"notice":"GroundRules: Original legal text. Not legal advice."}