[Code of Federal Regulations]
[Title 40, Volume 31]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1065.290]

[Page 711]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents
 
                    Subpart C_Measurement Instruments
 
Sec.  1065.290  PM gravimetric balance.

    (a) Application. Use a balance to weigh net PM on a sample medium 
for laboratory testing.
    (b) Component requirements. We recommend that you use a balance that 
meets the specifications in Table 1 of Sec.  1065.205. Note that your 
balance-based system must meet the linearity verification in Sec.  
1065.307. If the balance uses internal calibration weights for routine 
spanning and linearity verifications, the calibration weights must meet 
the specifications in Sec.  1065.790. While you may also use an inertial 
balance to measure PM, as described in Sec.  1065.295, use a reference 
procedure based on a gravimetric balance for comparison with any 
proposed alternate measurement procedure under Sec.  1065.10.
    (c) Pan design. We recommend that you use a balance pan designed to 
minimize corner loading of the balance, as follows:
    (1) Use a pan that centers the PM sample 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.
    (2) Use a pan that positions the PM sample as low as possible.
    (d) Balance configuration. Configure the balance for optimum 
settling time and stability at your location.