R18-2-524. Renumbered 

Historical Note

Adopted effective May 14, 1979 (Supp. 79-1). Amended effective July 9, 1980 (Supp. 80-4). 

Amended subsection (A) effective September 22, 1983 (Supp. 83-5). Former Section R9-3-524 

renumbered without change as Section R18-2-524 (Supp. 87-3). Amended effective September 

26, 1990 (Supp. 90-3). Renumbered to R18-2-724 effective November 15, 1993 (Supp. 93-4).

R18-2-724. Standards of Performance for Fossil-fuel Fired Industrial and Commercial 

Equipment

A. This Section applies to industrial and commercial installations which are less than 73 megawatts 

capacity (250 million Btu per hour), but in the aggregate on any premises are rated at greater 

than 500,000 Btu per hour (0.146 megawatts), and in which fuel is burned for the primary 

purpose of producing steam, hot water, hot air or other liquids, gases or solids and in the course 

of doing so the products of combustion do not come into direct contact with process materials. 

When any products or by-products of a manufacturing process are burned for the same purpose 

or in conjunction with any fuel, the same maximum emission limitations shall apply.

B. For purposes of this Section, the heat input shall be the aggregate heat content of all fuels whose 

products of combustion pass through a stack or other outlet. The heat content of solid fuel shall 

be determined in accordance with R18-2-311. Compliance tests shall be conducted during 

operation at the nominal rated capacity of each unit. The total heat input of all fuel-burning 

units on a plant or premises shall be used for determining the maximum allowable amount of 

particulate matter which may be emitted.

C. No person shall cause, allow or permit the emission of particulate matter, caused by combustion 

of fuel, from any fuel-burning operation in excess of the amounts calculated by one of the 

following equations:

1. For equipment having a heat input rate of 4200 million Btu per hour or less, the maximum 

allowable emissions shall be determined by the following equation:

E = 1.02Q0.769

where:

E = the maximum allowable particulate emissions rate in pounds-mass per hour.

Q = the heat input in million Btu per hour.

2. For equipment having a heat input rate greater than 4200 million Btu per hour, the maximum 

allowable emissions shall be determined by the following equation:

E = 17.0Q0.432

where “E” and “Q” have the same meanings as in subsection (C)(1).

D. Actual values shall be calculated from the applicable equations and rounded off to two decimal 

places.

E. Fossil-fuel fired industrial and commercial equipment installations shall not emit more than 1.0 

pounds of sulfur dioxide per million Btu heat input when low sulfur oil is fired.

F. Fossil-fuel fired industrial and commercial equipment installations shall not emit more than 2.2 

pounds of sulfur dioxide per million Btu heat input when high sulfur oil is fired.
G. Any permit issued for the operation of an existing source, or any renewal or modification of 

such a permit, shall include a condition prohibiting the use of high sulfur oil by the permittee. 

This condition may be omitted from the permit if the applicant demonstrates to the satisfaction 

of the Director both that sufficient quantities of low sulfur oil are not available for use by the 

source and that it has adequate facilities and contingency plans to ensure that the sulfur dioxide 

ambient air quality standards set forth in R18-2-202 will not be violated. 

1. The terms of the permit may authorize the use of high sulfur oil under such conditions as 

are justified. 

2. In cases where the permittee is authorized to use high sulfur oil, it shall submit to the 

Department monthly reports detailing its efforts to obtain low sulfur oil. 

3. When the conditions justifying the use of high sulfur oil no longer exist, the permit shall be 

modified accordingly. 

4. Nothing in this Section shall be construed as allowing the use of a supplementary control 

system or other form of dispersion technology.

H. When coal is fired, fossil-fuel fired industrial and commercial equipment installations shall not 

emit more than 1.0 pounds of sulfur dioxide per million Btu heat input.

I. The owner or operator subject to the provisions of this Section shall install, calibrate, maintain 

and operate a continuous monitoring system for measurement of the opacity of emissions 

discharged into the atmosphere from the control device.

J. For the purpose of reports required under excess emissions reporting required by R18-2-310.01, 

the owner or operator shall report all six-minute periods in which the opacity of any plume or 

effluent exceeds 15%.

K. The test methods and procedures required by this Section are as follows:

1. The reference methods in 40 CFR 60, Appendix A, as incorporated by reference in Appendix 

2 of this Chapter, shall be used to determine compliance with the standards as prescribed 

in this Section.

a. Method 1 for selection of sampling site and sample traverses,

b. Method 3 for gas analysis to be used when applying Reference Methods 5 and 6,

c. Method 5 for concentration of particulate matter and the associated moisture content,

d. Method 6 for concentration of SO2.

2. For Method 5, Method 1 shall be used to select the sampling site and the number of traverse 

sampling points. The sampling time for each run shall be at least 60 minutes and the 

minimum sampling volume shall be 0.85 dscm (30 dscf), except that smaller sampling 

times or volumes, when necessitated by process variables or other factors, may be approved 

by the Director. The probe and filter holder heating systems in the sampling train shall be 

set to provide a gas temperature no greater than 160°C. (320°F.).

3. For Method 6, the sampling site shall be the same as that selected for Method 5. The 

sampling point in the duct shall be at the centroid of the cross section or at a point no closer 

to the walls than 1 m (3.28 ft). For Method 6, the sample shall be extracted at a rate 

proportional to the gas velocity at the sampling point.

4. For Method 6, the minimum sampling time shall be 20 minutes and the minimum sampling 

volume 0.02 dscm (0.71 dscf) for each sample. The arithmetic mean of two samples shall 

constitute one run. Samples shall be taken at approximately 30-minute intervals.

5. Gross calorific value shall be determined in accordance with the applicable ASTM methods: 

D-2015-91 (Test for Gross Calorific Value of Solid Fuel by the Adiabatic Bomb 

Calorimeter) for solid fuels; D-240-87 (Test Method for Heat of Combustion of Liquid 
Hydrocarbon Fuels by Bomb Calorimeter) for liquid fuels; and D-1826-88 (Test Method 

for Calorific Value of Gases in Natural Gas Range by Continuous Recording Calorimeter) 

for gaseous fuels. The rate of fuels burned during each testing period shall be determined 

by suitable methods and shall be confirmed by a material balance over the fossil-fuel fired 

system.

Historical Note

Section R18-2-724 renumbered from R18-2-524 and amended effective November 15, 1993 

(Supp. 93-4). Amended by final rulemaking at 7 A.A.R. 1164, effective February 15, 

2001 (Supp. 01-1). Amended by final rulemaking at 15 A.A.R. 281, effective March 7, 

2009 (Supp. 09-1).