Commonwealth of Pennsylvania

Environmental Protection

April 2, 1998

Subject: Source Test Review

Letterkenny Army Depot

Greene Township, Franklin County

To: Rick Millard

Air Pollution Control Engineer

Southcentral Regional Office

From: Robert Small

Air Pollution Control Engineer

Division of Source Testing and Monitoring

Bureau of Air Quality

Through: L. Blaine DeHaven

Chief

Division of Source Testing and Monitoring

Bureau of Air Quality

Timothy R. Brooks

Chief

Source Testing Section

Division of Source Testing and Monitoring

Bureau of Air Quality

Letterkenny Army Depot operates chromium electroplating line #1 consisting of one chrome 

alkaline strip tank (tank 1), three chrome plating tanks (tanks 2-4), and one black chrome plating 

tank (tank 5) at the above location.

Each tank has variable holding capacities and bath lives. The ferrous metal parts are dipped into 

the tanks until properly electroplated, rinsed off and dried. The emissions from each tank are 

pulled by a 40,000 cfm I.D. fan through the ventilation system and exhausted to a VANAIRE, 

Ltd. composite mesh pad chrome mist eliminator (fume scrubber). The emissions from the 

scrubber are then discharged to the atmosphere through a 48-inch inside diameter stack.

On August 6, 1997, personnel from Vanaire conducted chromium (Cr) emission testing in the 

exhaust stack serving tank nos. 1-5 utilizing EPA Method 306A and analyzed the samples using 

inductively coupled plasma emission spectrometry (ICP). The purpose of the test was to 

demonstrate compliance with a NESHAP MACT standard of 0.015 mg/dscm as listed in 40 

CFR, Subpart N, Section 63.342 (c) (1) (i) and establish the pressure drop across the system. 

Testing was conducted in accordance with acceptable sampling practices and the conditions of 

the approved test protocol with the following comments:
Data File

Letterkenny Army Depot

Greene Township, Franklin County 2 April 2, 1998

The test samples were analyzed utilizing the graphite furnace atomic absorption (GFAAS) 

analytical technique since ICP results were below the minimum detection limit required by the 

method. ICP results are only acceptable if chromium concentrations of 35 ug/l or greater are 

measured or the calculated emission results are determined to be at least 5 times lower than 

emission standard.

Only one set of pressure drops across the control system were recorded in the test report. The 

consultant stated that the technician monitored pressure drops across control system during all 

three test runs observing no significant change in readings.

The recalculated emission concentrations were determined by utilizing GFAAS weights (not 

shown in the original test report) of 8.6, 7.2 and 4 micrograms. The test results are considered 

marginally acceptable to the Department because pressure drops across control system were not 

recorded during all three test runs.

The following data was extracted from the test report:

Chromium Emission Summary for Chrome Plating Line #1

Test Date 08/06/97

Test Run Number 1 2 3

Pressure Drop during testing

(in H2O)

Stage 1 - 0.15, Stage 2 - 0.06 & Stage 3 - 2.6

2.81 Total

Cr Emission Concentration, (mg/dscm) 0.0051 0.0037 0.0029

Allowable Cr Emission Concentration, (mg/dscm) 0.015

*Note: Recalculated results utilizing GFAAS method concentrations of 8.6, 7.2 and 4 micrograms.
Data File

Letterkenny Army Depot

Greene Township, Franklin County 3 April 2, 1998

Tanks Contents During Testing

Tank Cell Current

(ampere)

Contents Surface Area

(ft2)

1 1

2

650

475

1 ea. Recuperator Cylinder & 1 ea. Elevation Cylinders

4 ea. Dummy Loads

7.58

15.76

2 1

2

1800

1600

2 ea. Elevation Cylinders

2 ea. Piston Rods

7.88

5.38

3 1

2

3

4

5

1800

1800

1600

1800

1600

2 ea. Elevation Cylinders

2 ea. Recuperator Cylinders

2 ea. Piston Rods

2 ea. Recuperator Cylinders

2 ea. Piston Rods

7.88

7.28

5.38

7.28

5.38

4 1

2

3

4

1800

1600

800

1600

2 ea. Elevation Cylinders

2 ea. Piston Rods

1 ea. Piston Rods

2 ea. Piston Rods

7.88

5.38

2.69

5.38

5 1 1600 1 ea. M45 Rail 2.02

93.15

cc: Plan Approval No. 28-318-012C

Reading File - Source Testing Section

Data File - Stack Testing

Compliance & Enforcement - Scott Kepner

Division of Permits

EPA/TRB