SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

ATTACHMENT B

COMMENTS AND RESPONSES

The following comments include those received from the U.S. EPA in their June 2011 

Technical Support Documents, at the Task Force meeting held on July 11, 2013 and the 

Public Workshop meeting held on August 28, 2013 as well as written comments received 

on or before September 13, 2013.

1. Comment: To improve clarity and enforceability it is recommended adding a definition 

for “unscheduled repair”, “as-found operating conditions”, and “breakdown conditions”.

Response: Such descriptions referring to equipment shutdown is addressed in other 

District rules. Therefore, there is no need to incorporate such definitions in rules 1146 and 

1146.1.

2. Comment: In measuring CO emissions both rules allow the use of a source test or the 

portable analyzer as part of the diagnostic emission check. However, the protocol for the 

diagnostic emission test requires the measurement of CO emissions along with NOx 

emissions. Consequently, the owner or operator does not have a choice in the way in 

which CO emissions are measured.

Response: Staff agrees with the comment and has proposed to modify the rule language 

to reflect current protocol practice by clarifying that the CO measurements will be done as 

part of both the source test and the diagnostic emission check. This change is considered 

to be administrative because there is no impact on the emissions, no change in the way in 

which the rules have been implemented, and no impact on costs.

3. Comment: Add definitions of "diagnostic emission check" and "source test" to both of 

the rules.

Response: Typically a definition is included in a rule if the term to be defined is not 

described in the rule. Both "diagnostic emission check" and "source test" are described in 

subdivision (d) of both Rule 1146 and 1146.1. On this basis, definitions for these terms 

are not necessary.

4. Comment: Appendix IV-B “Stationary Source Control Measures – Area Sources” of the 

1991 AQMP included control measure CM #90-D-2. This control measure proposed the 

use flat plate solar collectors, low NOx burners or equivalent control technology to reduce 

NOx emissions from swimming pool water heaters. Swimming pool water heaters are 

regulated under Rule 1121 “Control of Nitrogen Oxides from Residential - Type, Natural-
Gas-Fired Water Heaters”. Based on this information the application of flat plate solar 

collectors should be extended to Rules 1146 and 1146.1.

Response: CM #90-D-2 addresses the reduction of NOx emission from residential 

swimming pool heaters under Rule 1121 but not for the much larger boilers and heaters 

regulated under Rules 1146 and 1146.1. However, Rules 1146 and 1146.1, as in other 

SCAQMD rules, do not specify the manner in which emission reductions are achieved.

Thus, the owner or operator of Rule 1146 and 1146.1 equipment is not precluded from 

using flat plate solar collectors in demonstrating rule compliance.

5. Comment: For Rules 1146(c)(5) and 1146.1(c)(5) there appears to be a mislabeling of 

paragraphs which led to an unintentional requirement to test for CO emissions, even when 

low-fuel usage units do not require a source test or diagnostic emission check. The 

previous version of the rule, and the staff report made it clear that it was the intention to 

only require periodic tune-ups for this category of units.

Response: Staff agrees with the comment and has proposed changes to the rules to correct 

the rule language.

2