USAF Dehumidification Efforts for

Corrosion Control

2d Lt Kevin Cheng

Corrosion Engineer

AF Corrosion Prevention and Control Office

AFRL/RXSSR

August 16, 2011

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1. REPORT DATE 16 AUG 2011 2. REPORT TYPE

3. DATES COVERED 00-00-2011 to 00-00-2011

4. TITLE AND SUBTITLE USAF Dehumidification Efforts for Corrosion Control

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6. AUTHOR(S) 5d. PROJECT NUMBER

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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Air Force Corrosion Prevention & Control Office(AFCPCO),AFRL/RXSSR,325 Richard Ray Blvd, Bldg 165,Robins AFB ,GA,31098

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13. SUPPLEMENTARY NOTES Presented at the 2011 Air Force Corrosion Conference held 16-18 Aug 2011 at Robins AFB, GA.

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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

2

Overview

• Fundamental Corrosion Control

• Why DH

• DH Concept

• Current DH Efforts

• Green Shelter

• Control Humidity Protection Shelters

• DH Evaluations

• AFCPCO goals

20 December 2011

3

Fundamental Corrosion Control

• Corrosion Conditions

• Anode

• Cathode

• Electrolyte

• Electrical Contact

• Humidity vs. Corrosion

• Corrosion rate increases exponentially above 50% RH

• Typical control range: 30-50% RH

• Anything below 30% could lead to static charge buildup

20 December 2011

CONCEPT: BREAK THE CORROSION CIRCUIT BY

REMOVING THE CONDUCTIVE ELECTROLYTE

4

Why DH

• 15%- 20% electronic failures due to moisture

induced corrosion

• DH most effective method to protect equipment from

corrosion

• Seen 9 to 1 ROI

– Reduced maintenance costs

– Improved reliability

20 December 2011

0 20 40 60 80 100 0

0.4

0.6

0.8

1.0

0.2

Relative Humidity (%)

Re

lati

ve

Ra

te

Electronic Failures

Co

ntr

oll

ed

Hu

mid

ity

Pro

tec

tio

n

5

DH Concept

• Dehumidification (DH) can be achieved by:

• Cooling - vapor condensation

• Heating - air expansion

• Desiccants - materials with high affinity for water

• Combination thereof

• DH can be Sheltered or

Unsheltered

• Air Dehydration Units

- Uses a self rejuvenating

desiccant wheel

dehumidifier

- Closed or open loop

20 December 2011

6

Current DH Efforts

• Unsheltered Controlled

Humidity Protection

– Uses mobile DH units

– Reduces moisture

derogation of avionics and

electronic systems

• Current CHP efforts

– KC-135, Hickam AFB, HI

– F-16, McEntire ANG, SC

– C-130, McEntire ANG, SC

– F-22, Tyndall AFB, FL

20 December 2011

7

Current DH Efforts

• General Location of Most LRU’s Dehumidified

20 December 2011 7

3R 6R

Bay 5

10R

8

Current DH Efforts

20 December 2011

9

Current DH Efforts

• Sheltered Controlled

Humidity Protection

– Climate controlled

– For aircraft and AGE

• Current efforts

– AGE, Savannah ANG, GA

• AFCPCO Green Shelter test

– AGE, Hickam AFB, HI

• Future Shelter efforts

– F-22, Hickam AFB, HI

– Kadena AB, Japan

20 December 2011

10

The Green Shelter

Dehumidification Unit

Retractable

Sealed Booth

Soft Wall

Maintenance

Shelter

Stored

AGE

Renewable energy powers dehumidification equipment (DH)

DH maintains dry air

in storage booths,

protecting AGE

equipment from

corrosion and

moisture infiltration

Booth contained in maintenance shelter for added corrosion protection and a comfortable working environment

LED lighting

also powered

by renewable

energy

11

CHP Shelters

• Used to prevent corrosion

on outer skin

• Being developed for the F-22

at Hickam AFB

• Pre-Engineered Steel

Structure designed

specifically for DH

20 December 2011

12

DH Evaluation

20 December 2011

Nov

40

35

30

25

20

15

10

5

Nu

mb

er

of

R2

Ac

tio

ns

R

Jan Dec Feb Mar Apr May Jun Jul

14

37

24

41

8

12

15

33

29

15 14

24

21

13

21

17

12

2

23

21

Aug Sep

26

15

27

3

Oct

13

26

Blue After CHP 161

Red Before CHP 306

Totals this chart:

F-15A/B LRU Remove & Replace (R2) Comparison: R2 Actions Reduced by 47% After CHP

13

DH Evaluation

20 December 2011

300

200

100

329

163

Before CHP

Nov 05 thru Oct 06

Average possessed acft: 19

Cost

LR

U Q

ua

nti

ty

LR

U C

os

t:

Th

en

ye

ar

$M

$8.4 M

$4.2 M

After CHP

Nov 06 thru Oct 07

Average possessed acft: 14

Cost

Qty

Qty

Issue Costs and Quantities 50 % Less After CHP

($4.2M & 166 LRU’s Less After CHP) 400

2

4

8

6

16 CHP Slots

Used avg

47% of time

for all A/B/C/D

model F-15s

10

F-15 A/B LRU Cost & Quantity Comparison After 12 Months

14

DH Evaluations

20 December 2011

Service Timeframe Equipment Results

RAF 2000s Tornados 24% decrease in “no fault” discrepancies 15% decrease in avionics maintenance

US Navy 1993 EP-3 Aries Avionics reliability improved 25% Increased MTBF 7-30%

US Navy 1995 A-6E Intruder Increased MTBF 21%

US Army 1997-1998 UH-60 Blackhawk

Savings of $2.2 million

15

DH Evaluations

20 December 2011

Service Timeframe Equipment Results

USAF 2006 KC-135, Hickam TBD

USAF 2006 F-15, Hickam R2 actions reduced by 47% Labor hours reduced by 31% monthly

USAF 2008 F-16, McEntire TBD

USAF (AFCPCO)

2009 AGE, Savannah 50% Decrease in corrosion from sealed booth to shelter 50% Decrease in corrosion from shelter to outside

USAF 2011 F-22, Tyndall TBD

16

AFCPCO goals

• Condition-based maintenance (CBM+) • High Velocity Maintenance (C-130)

• Maintenance Steering Group (MSG-3)

• New DH chapter on TOs • 1-1-691

• 35-1-3

• -23

• Expeditionary Combat Support System (ECSS)

20 December 2011

17

Summary

• Fundamental Corrosion Control

• Why DH

• DH Concept

• Current DH Efforts

• Green Shelter

• Control Humidity Protection Shelters

• DH Evaluations

• AFCPCO goals

20 December 2011

18

Questions

20 December 2011

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