part_subject: "CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS"
subpart_code: "D"
subpart_subject: "Emission Test Equipment Provisions"
section_number: "90.326"
section_subject: "Pre- and post-test analyzer calibration."
cfr_reference: "40 CFR 90.326"
title_name: "Title 40"
title_subject: "Protection of Environment"
parts_covered: "Parts 87 to 95"
revised_date: "Revised as of July 1, 2017"
publication_date: "As of July 1, 2017"
contains_description: "Containing a codification of documents of general applicability and future effect"
publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"
---
Calibrate only the range of each analyzer used during the engine exhaust emission test prior to and after each test in accordance with the following:
(a)Make the calibration by using a zero gas and a span gas. The span gas value must be between 75 and 100 percent of the highest range used.
(b)Use the same analyzer(s) flow rate and pressure as that used during exhaust emission test sampling.
(c)Warm-up and stabilize the analyzer(s) before the calibration is made.
(d)If necessary clean and/or replace filter elements before calibration is made.
(4)If the response of the zero gas or span gas differs more than one percent of full scale at the highest range used, then repeat paragraphs (e)(1) through (3) of this section.