EQUIPMENT DESCRIPTION:

SPRAY BOOTH, FLOOR TYPE, XYZ MANUFACTURING, MODEL Acme, 7’–0" W. X 20’–0" L. X  7’–10" H., WITH TWO 40" X 80" PRE-FILTERS, SIXTEEN 20" W. X 20" L. X 3" D. FINAL HEPA FILTERS, AND ONE 2 HP EXHAUST FAN.

HISTORY AND BACKGROUND:

ACME Coatings. ("applicant") has submitted one application for a Permit to Operate for one spray booth. There is no other equipment at this facility. This is a typical aerospace coating facility. ACME has been operating this facility at this location since 1998. Prior to this, DEF Inc. operated the equipment under permit D123BC but let the permit lapse until the change of ownership occurred. Applicant was issued a Notice of Violation for operating the equipment without a permit which is the reason for filing this application. In addition to this facility, the applicant has another facility located at 34 Copley Drive, Diamond Bar (ID No. 99999).

PROCESS DESCRIPTION:

The applicant will use this booth to apply various coatings to Aerospace parts. The process is a batch operation. The parts are placed in the spray booth when they are ready to be coated. The coating is applied to the part using a high-volume, low-pressure (HVLP) spray gun. Once the coating is applied, the part is allowed to air-dry. Any overspray (particulate) is exhausted through the pre-filters as well as the HEPA filters before it is vented to the atmosphere. A gauge is installed to measure the pressure drop across the filters. The spray gun is cleaned using a compliant solvent in an enclosed gun-cleaning system or by using non-atomized flow into a closed container. The company plans to operate the equipment 5 days per week, 50 weeks per year.

EMISSION CALCULATIONS:

The use of coatings and solvents in this booth will result in emissions of ROG, TOG, and Rule 1401 compounds. The applicant has requested use of three gallons of coating per day, which allows the facility to be exempt from the requirements of Rule 1124. The facility will be spraying a coating that contains strontium chromate, which is a Rule 1401 carcinogenic air contaminant.

Based on the three gallons of coatings usage per day the VOC emissions will amount to 17 pounds per day.

Chromium Emissions

The applicant has requested that a maximum of 16 gallons per year of Courtalds Aerospace Product No. 513X408B be used. The MSDS submitted indicates that this coating contains 15% by weight strontium chromate, with a product density of 10.55 pounds per gallon. For Rule 1401 purposes, we are only interested in the hexavalent chromium portion of the strontium chromate. As a worst case assumption, we will assume that all the chromium is hexavalent (as opposed to trivalent).

The structure of strontium chromate is SrCrO₄. Therefore, the portion of this compound that is hexavalent chromium is calculated as follows:

Given:

Molec. Wt. of Strontium = 87.62

Molec. Wt. of Chromium = 51.996

Molec. Wt. of Oxygen = 15.999

%Chromium = (51.996)/{(87.62) + (51.996) + (15.999 x 4)} = 25.54%

pounds of chromium per gallon = (10.55 lb/gal)(0.15)(0.2554) = 0.4042

Annual chromium sprayed = (16 gal/yr) (0.4042) = 6.4672 lb/yr

To calculate the controlled and uncontrolled chromium emissions the following will be used:

Assumptions:
    transfer efficiency = 65%
    Fallout = 50%
    filter efficiency = 99.97%

Chromium_uncontrolled = (6.4672 lb/yr)(1 - 0.65)(1 – 0.50) = 1.1318 lb/yr

Chromium_controlled = (1.1318 lb/yr)(1 - 0.9997) = 0.0003395 lb/yr

Using this annual emission rate for hexavalent chrome, the corresponding MICR is calculated:

For the nearest receptor (Off-site worker)

Q = 0.1698 x 10^-6 tons/yr

X/Q = 51.18 (ug/m³)(tons/yr)

MET = 0.57 (Burbank)

MP = 1.01

LEA = 0.66

U_chromium = 1.5 x 10^-1 (ug/m³)^-1

MICR = (Q)(X/Q)(MET)(U)(MP)(LEA)
           = (0.1698 x 10^-6)(51.18)(0.57)(1.5 x 10^-1)(1.01)(0.66) = 0.495 x 10^-6

For the nearest residential receptor

Q = 0.1698 x 10^-6 tons/yr

X/Q = 4.51 (ug/m³)(tons/yr)

MET = 0.57 (Burbank)

MP = 1.01

LEA = 1.0

U_chromium = 1.5 x 10^-1 (ug/m³)^-1

MICR = (Q)(X/Q)(MET)(U)(MP)(LEA) =
           = (0.1698 x 10^-6)(4.51)(0.57)(1.5 x 10^-1)(1.01)(1.0) = 0.066 x 10^-6

As shown, the risk for the nearest industrial receptor is much higher than for the nearest residential. In order to give the applicant some degree of flexibility, the annual usage will be limited to 24 gallons, and the weight percent will be limited to 20%. Inserting these numbers into the equation, the final MICR will be 0.825-in-a-million, still under the one-in-a-million.

In addition to the strontium chromate, the applicant has indicated that the following compounds with acute risk values will be used:

Compound CAS # Screening Level

Ethylene glycol monobutyl ether 111-76-2 7.0 lb/hr

Methyl ethyl ketone 78-93-3 6.5 lb/hr

Toluene 108-88-3 18.5 lb/hr

Xylene 1330-20-7 11.0 lb/hr

The maximum spraying rate in a typical HVLP spray gun is about 1.0 gallon per hour. Assuming a coating density of about 10 pounds per gallon, the xylene and toluene limits would never be exceeded. As for MEK and EGBE, a permit condition that limits the content of either of these compounds to 50% by weight will be imposed.

RULES:

RULE 212 A public notice is not required. The installation of this equipment is not considered a significant project because:

a. this equipment will not be located within 1000 feet of a school
b. the emissions are less than the limits in subdivision (g), and
c. the toxic air contaminants are within acceptable levels

RULE 401 Visible emissions are not expected with proper maintenance and operation of this equipment.

RULE 402 Operation of equipment is not expected to create a nuisance.

RULE 403 Fugitive particulate emissions are not expected from this equipment with proper maintenance and operation.

RULE 1124: Does not apply. Usage of coatings and solvents less than 3 gal/day.

RULE 1171: MSDS provided demonstrates compliance with the rule.

REG. XIII 1303(a): HEPA filters are considered to be BACT for control of particulate. The ROG emissions are below the levels for which add-on control is required.

1303(b)(1): The particulate emissions are below the levels in Table A-1, and thus, no further analysis is required. Modeling is not required for ROG.

1303(b)(2): The particulate and ROG emissions are below the threshold, thus no offsets are required.

1303(b)(4): The facility is expected to be in full compliance with all applicable rules and regulations of the District.

RULE 1401 As shown, the Toxic Air Contaminants are below the acceptable limits. The permit will be conditioned as such to ensure compliance with this rule.

CONCLUSIONS/RECOMMENDATIONS:

This equipment complies with all District Rules and Regulations. Issue a Permit to Operate subject to the conditions listed on the sample permit that follows this report.

Conditions:

1) OPERATION OF THIS EQUIPMENT SHALL BE CONDUCTED IN ACCORDANCE WITH ALL DATA AND SPECIFICATIONS SUBMITTED WITH THE APPLICATION UNDER WHICH THIS PERMIT IS ISSUED UNLESS OTHERWISE NOTED BELOW.

2) THIS EQUIPMENT SHALL BE PROPERLY MAINTAINED AND KEPT IN GOOD OPERATING CONDITION AT ALL TIMES.

3) THIS SPRAY BOOTH SHALL NOT BE OPERATED UNLESS ALL EXHAUST AIR PASSES THROUGH PRE-FILTER MEDIA AT LEAST TWO INCHES THICK AS WELL AS HEPA FILTERS (RATED AT 99.97% AT 0.3 MICRONS).

4) A GAUGE SHALL BE INSTALLED TO INDICATE, IN INCHES OF WATER, THE STATIC PRESSURE DIFFERENTIAL ACROSS THE EXHAUST FILTERS. IN OPERATION, THE PRESSURE DIFFERENTIAL SHALL NOT EXCEED 1.0 INCHES OF WATER.

5) THE TOTAL QUANTITY OF COATINGS, REDUCERS, ADHESIVES, CLEAN-UP SOLVENTS USED IN THIS EQUIPMENT SHALL NOT EXCEED 3 GALLONS IN ANY ONE DAY.

<6) THE TOTAL QUANTITY OF COATINGS THAT CONTAIN STRONTIUM CHROMATE SHALL NOT EXCEED 2 GALLONS PER MONTH.

7) THE CONTENT OF STRONTIUM CHROMATE IN ANY COATING USED IN THIS EQUIPMENT SHALL NOT EXCEED 20.0 PERCENT BY WEIGHT.

8) THE CONTENT OF METHYL ETHYL KETONE (CAS# 78-93-3) IN ANY COATING OR SOLVENT USED IN THIS EQUIPMENT SHALL NOT EXCEED 50% BY WEIGHT.

9) THE CONTENT OF ETHYLENE GLYCOL MONOBUTYL ETHER (CAS# 111-76-2) IN ANY COATING OR SOLVENT USED IN THIS EQUIPMENT SHALL NOT EXCEED 50% BY WEIGHT.

10) THIS EQUIPMENT SHALL BE OPERATED IN COMPLIANCE WITH RULE 1171.

11) MATERIAL SAFETY DATA SHEETS FOR ALL VOC-CONTAINING MATERIALS USED AT THIS FACILITY SHALL BE KEPT CURRENT AND MADE AVAILABLE TO DISTRICT PERSONNEL UPON REQUEST.

12) MATERIALS USED IN THIS EQUIPMENT SHALL NOT CONTAIN ANY COMPOUNDS IDENTIFIED AS TOXIC AIR CONTAMINANTS IN RULE 1401, TABLE I, (EXCEPT FOR STRONTIUM CHROMATE-CAS#7789-06-2, METHYL ETHYL KETONE-CAS# 78-93-3,ETHYLENE GLYCOL MONOBUTYL ETHER-CAS# 111-76-2, TOLUENE-CAS# 108-88-3, AND XYLENE-CAS# 1330-20-7), WITH A DATE OF LISTING OF AUGUST 13, 1999 OR EARLIER.

13) IN ADDITION TO THE RECORDKEEPING REQUIREMENTS OF RULE 109, THE OPERATOR SHALL KEEP ADEQUATE RECORDS FOR THIS FACILITY TO VERIFY DAILY USAGE FOR EACH COATING AND SOLVENT USED IN THIS EQUIPMENT, AS WELL AS THE WEIGHT PERCENT OF EACH COMPOUND REFERENCED IN CONDITION NO. 12. ALL RECORDS SHALL BE PREPARED IN A FORMAT THAT IS ACCEPTABLE TO THE DISTRICT, AND SHALL BE RETAINED ON THE PREMISES FOR AT LEAST TWO YEARS, AND SHALL BE MADE AVAILABLE TO DISTRICT PERSONNEL UPON REQUEST.