Commonwealth of Pennsylvania

Environmental Protection

April 9, 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 #2 consisting of three hard

chrome plating tanks (tanks 6-8) at the above location.

Ferrous metal parts are dipped into the tanks until properly electroplated, rinsed off and dried. 

The emissions from each tank are pulled by a 24,000 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 36-

inch inside diameter stack.

On October 22-23, 1997, personnel from Vanaire conducted chromium (Cr) emission testing in 

the exhaust stack serving tank nos. 6-8 utilizing EPA Method 306A and analyzed the samples 

using graphite furnace atomic absorption (GFAAS). 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. Except for the 

following deviation, testing was conducted in accordance with acceptable sampling practices and 

the conditions of the approved test protocol:
Data File

Letterkenny Army Depot

Greene Township, Franklin County 2 April 9, 1998

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 emission concentrations were calculated correctly and appear to be valid. However, as with 

August 6 test program performed by Vanaire on company’s electroplating line #1 (tanks 1-5), the 

test results are considered marginally acceptable to the Department because pressure drops across 

control system were not recorded during all three test runs (see review memorandum dated April 

2, 1998).

The following data was extracted from the test report:

Chromium Emission Summary for Chrome Plating Line #2

Test Date 10/22/97 10/22/97 10/22/97

Test Run Number 1 2 3

Pressure Drop during testing

(in H2O)

Stage 1 - 0.10, Stage 2 - 0.60 & Stage 3 - 2.0

2.70 Total

Cr Emission Concentration, (mg/dscm) 0.0026 0.0039 0.0032

Allowable Cr Emission Concentration, (mg/dscm) 0.015

Tanks Contents During Testing

Tank Cell Current

(ampere)

Contents Surface Area

(ft2)

6 1

2

3

4

5

800

850

800

800

850

1 ea. Piston Rod

1 ea. Recuperator Cylinders

1 ea. Piston Rod

1 ea. Piston Rod

1 ea. Recuperator Cylinder

2.69

3.64

2.69

2.69

3.64

7 1

2

3

4

800

850

800

850

1 ea. Piston Rod

1 ea. Recuperator Cylinder

1 ea. Piston Rod

1 ea. Recuperator Cylinder

2.69

3.64

2.69

3.64

5 800 1 ea. Piston Rod 2.69

8 1 1500 1 ea. M45 Rail 2.02

32.72
Data File

Letterkenny Army Depot

Greene Township, Franklin County 3 April 9, 1998

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

Reading File - Source Testing Section

Data File - Stack Testing

Compliance & Enforcement - Scott Kepner

Division of Permits

EPA/TRB