Q858. Under Calculation Method 2 for pneumatic devices, which is an available option beginning with Reporting Year 2024, must a device that is zero bleed except for actuation during emergencies and other unintended events (e.g., a wellhead emergency shutdown device) be forced to actuate in order to measure the emissions?

A858. No. First, per 40 CFR 98.233(a)(2), under Calculation Method 2 measurements are only required for pneumatic devices that are directly vented to the atmosphere. If the device is “zero bleed” because the device actuation emissions are routed back to the process or other similar vapor recovery system, then the device is not vented directly to the atmosphere and thus is not required to be measured. Second, a device that is “zero bleed” except when actuating and vents directly to the atmosphere when actuating is a device that vents directly to the atmosphere and  should be classified as an intermittent bleed device per the definition in 40 CFR 98.6 (regardless of the length of time between actuations or the reason for the actuation). Under Calculation Method 2, the device would be subject to measurement via the methods outlined in 40 CFR 98.233(a)(2). However, you are not required to cause an actuation of the device during the measurement period. If no emissions are measured from a device during the measurement period, Calculation Method 2 specifies that the emissions from the device must be estimated, and that for intermittent bleed pneumatic devices the estimate must be using the method specified in 40 CFR 98.233(a)(2)(v)(C)(2) through (5), which is based on engineering calculations using the volume of the controller, tubing, and actuator, the natural gas supply pressure, and the number of actuations that occurred during the year. For example, for an intermittent bleed device that had no measurable emissions under 40 CFR 98.233(a)(2)(iii) and no actuations of the device during the year under 40 CFR 98.233(a)(2)(v)(C)(2) through (5), then the emissions from that device would be zero.