MEMORANDUM 

January 25, 2010 

To: F. Tanaka 

Via: K. Kunaniec 

From: T. Underwood 

Re: Outside Test OS-3148; September 29, 30 and October 1, 2009 source 

test of emission point P-12 

Site No: A0051 

Plant No: 51; United Airlines 

Emission Pt: P-12 

Source No: S-18, S-19; Plating tanks 

Abated by: A-218, A-219; Dry scrubber with composite mesh pads 

Abated by: A-418; HEPA 

A/C No: Title V 

Conditions: 23542, Reg. 11-8 incorporates CARB Table 94102.4 by reference*: Cr+6

0.0015 mg/A-hr 

*Note: Databank and the Title V permit would be clearer if the actual emission 

limit were cited directly. 

By: Blue Sky Environmental 

I have reviewed the source test report cited above and note the following: 

1) Source test was properly notified (NST-1811). 

2) I did not witness the tests. 

3) The testing appears to have been conducted by personnel who are 

familiar with proper source testing techniques. 

4) Quality assurance procedures were adequate to assure data integrity. 

Despite sampling for six hours, the detection limit established was higher 

than the emission limit imposed on this source. Contributing factors could 

be laboratory error, handling error, or analyzer limitations. No retest is 

required.

5) Results of testing demonstrate these sources were in compliance with all 

of the conditions cited above. 

This source was in compliance with District Regulations. 
OS-3148

TABLE 1

Hexavalent and Total Chromium Emission Test Results

United Airlines San Francisco Maintenance Center

Stack P-12 [Sources S-18 and S-19]

RUN # 1 2 3 AVERAGE LIMITS

TEST DATE 9/29/09 9/30/09 10/1/09

TEST PERIOD 1053-1656 0724-1327 0856-1501

TEST DURATION, Mins 360 360 360

Total Plating amp-hours 3,031 3,331 3,427

Average amp-hr per hour 505 555 571

SAMPLE VOLUME DSCF 198.162 199.132 200.689

ISOKINETIC % 100.4 98.1 100.1 99.5

DUCT TEMP °F 66.9 84.1 82.2 77.7

VELOCITY ft/sec 41.90 44.45 43.43 43.26

FLOW RATE ACFM 7,895 8,375 8,182 8,151

FLOW RATE DSCFM 7,893 8,117 8,017 8,009

H2O % 1.06 0.96 0.89 0.97

O2 % 20.90 20.90 20.90 20.90

CO2 % 0.04 0.04 0.04 0.04

Total Chromium ug <0.97 <1.40 <1.50 <1.29

Total Chromium mg <0.00097 <0.00140 <0.00150 <0.00129

Total Chromium mg/DSCM <0.000173 <0.000248 <0.000264 <0.000228

Total Chromium gm/hr <0.0023 <0.0034 <0.0036 <0.0031

Total Chromium (MW=51.996) ppm <0.00008 <0.00011 <0.00012 <0.00011

Hexavalent Chromium ug <0.37 <0.41 <0.78 <0.52

Hexavalent Chromium mg <0.00037 <0.00041 <0.00078 <0.00052

Hexavalent Chromium mg/DSCM <0.000067 <0.000073 <0.000137 <0.000092

Hexavalent Chromium mg/hr <0.89 <1.01 <1.86 <1.26

Hexavalent Chromium mg/amp-hr <0.00177 <0.00181 <0.00326 <0.00228

Hexavalent Chromium (MW=51.996) ppm <0.00003 <0.00003 <0.00006 <0.00004

Applicable Limit is based on United Airlines Permit to Operate Condition and CARB Chrome Plate ATCM

Notes: Less than (<) signs precede the method detection limit.

WHERE, CALCULATIONS,

 < = Less Than mg/DSCM = 35.314 * mg/DSCF 

 Velocity = Stack gas velocity in feet per second gm/hr = 10-6 * 60 * DSCFM * (ug/DSCM) / 35.314 

 DSCFM = Dry Standard cubic feet per minute mg/amp-hr = (mg/DSCF)*DSCFM*60/ave amp-hr per hr

 ug/DSCM = micrograms per dry standard cubic meter ppm @ 68°F = 24.05 * (mg/dscm) / M.W.

 gm/hr = Emission rate, grams per hour

BLUE SKY ENVIRONMENTAL

0.015

0.0015

c:\documents and settings\blue sky\desktop\bluesky\2008 rpt\ual\ual m425 p-14 2008.xls - 1/26/2009