Investment Costs and Value 

Added Related to Enclosed 

Solvent Cleaning Machines

Dr Donald Gray

Chemical Engineering Dept

University of Rhode Island
OTVC Costs And Emissions Reduc
Airtight Degreasers

• End of pipe emission 

controls

• Slightly pressurized 

cleaning chamber

• Usually spray or 

immersion systems

• Vapor degrease at the 

normal boiling point of the solvent only
Airless Degreasers 

• Pollution prevention at 

the source

• Vacuum to high 

pressure degreasing

• Spray, immersion and 

vapor degreasing systems

• Vapor degrease at 

temperatures below or above NBP of solvent
Advantage In Using An OTV

Degreaser

• Low capital 

investment

• Simple to operate• Long time 

investment recovery for small unit

CAPITAL COSTS OF SOLVENT DEG

$0

$50,000

$100,000$150,000$200,000$250,000$300,000$350,000

0.0 5.0 10.0 15.0 20.0 25.0 

SQUARE FEET OF OT

TOTAL COST
Lower Labor Requirement

• Automated soak• Automated spray• Automated degrease

OPERATING COST COMPARISON

$0

$5,000

$10,000$15,000$20,000$25,000$30,000$35,000$40,000

OTVC $ AIRTIGHT DEGR $ AIRLESS DEGR $

$ / YEAR

* MISCELL $REPORTING $UTILITY $LABOR $SOLV WASTE $WASTE $SOLVENT $

•Automated •All of the abbe multiple s
Low Solvent Usage

• Reduced cost• Exemption from 

reporting

• Less shipping an

handling

• Less storage

OPERATING COST COMPARISON

$0

$10,000$20,000$30,000$40,000$50,000$60,000$70,000$80,000

OTVC $ AIRTIGHT DEGR $ AIRLESS DEGR $

$ / YEAR

* MISCELL $REPORTING $UTILITY $LABOR $SOLV WASTE $WASTE $SOLVENT $

RETURN

INFO RMATION

EPA MODELS DEGREASER SIZE 4.6 

 OVERALL COST COMPARISONS

ALL $ IS COST / YEAR OTVC $ AIRTIGHT DEGR $ SOLVENT $ $24,870 $7,485 

WASTE $ $420 $420 SOLV WASTE $ $8,262 $8,262 LABOR $ $23,526 $11,700 UTILITY $ $332 $332 REPORTING $ $583 $525 * MISCELL $ $12,974 $8,790 TOTAL OPER $ $70,968 $37,515 SAVING $ $24,404 $57,856 $ / LB METAL 0.197 0.104 

OPERA TING COST COMPA RIS
Safety To The Work Area

• Meet OSHA requirements• Comfort of operators• Easier introduction of new solvent• Reduced liability risk• Customer perception of the compa
Low Emissions To The 

Environment

• NESHAP 

compliance

• BACT / LAER 

standards

• Set MACT 

standards

• CLEANROOM 

applications

• AQMD approval

NESHAP COMPARISON ENCLOSED VS OT

0

50

100150200250300

0 500 1000 1500 2000 

LBS ALLOWED PER MONTH

CUBIC FEET (ENCLOSED
Better Quality Control

• System process times and steps are 

operator independent

• Cycle operation parameters can be 

collected

• System is load size independent• Menus can be used for specific part
Flexible Operating Temperat

• Wider application of solvents• Optimization of cleaning of various p• Longer solvent life• Greater uses for a given solvent
Better Cleaning Efficiency

• Solvent can operate above normal boil

point temperature and pressure

• Elimination of air pockets• Elimination of air-solvent surface tens

problems

• Rapid flushing with condensing heat 

transfer
Excellent Drying

• Solvent boils off part rather than evapo• Vacuum not site sensitive• Parts dried in an oxygen free environm• Parts can be dried at a lower temperatu
Increased Capacity

• Cleaning starts immediately in a vacuu• Solvent vapor tank can be custom size

match load

• Multiple chambers very economical• Different size chambers saves time and 

money
Can Use Many Solvents

• Elimination of oxygen allows for 

flammable solvents

• Unlimited solvent mixtures available 

for use

• Higher boiling solvents can clean with 

vapors
Reduced Reporting & Permit C

• Generally under 2000 lbs no reporting 

required

• NESHAP charges by the ton• Often no permitting required under 200
Energy Savings

• System is down 

when not cleaning

• System can operate 

at temperatures way below NBP

• Refrigeration not 

necessarily required

• No energy loss due 

to fugitive emissions
Reduced Waste Disposal

• Solvent concentration 

in waste reduced from 50% to 2%

• Possible to reduce 

bottoms to nonhazardous waste category

• Half the shipping, 

storage and handling

 SOLVENT CONCENTRATION IN WASTE AFTER DI

TCE IN CUTTING OIL

0

50

100150200250300

0% 5% 10% 15% 20% 25% 30% 35% 40% 

% SOLVENT IN WASTE

TEMPERTURE REQUIRED DEG F 
Enclosed Machines Cost Le

Depending on Solvent Cos

• Depends on solvent price

• TCE - $0.65

COST OF SOLVENT DEGREASING MACHINES

1 SHIFT, 6 HR WORKING, TCE, 3 YR PAYBACK

$0

$20,000$40,000$60,000$80,000

$100,000$120,000$140,000$160,000

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0

SQUARE FEET OF OTVC

$ / YEAR

OTVC OOTVC TAIRTIGAIRTIGAIRLESAIRLES
Enclosed Machines Cost Le

Depending on Solvent Cos

• Depends on solvent price

• NPB – $4.50

COST OF SOLVENT DEGREASING MACHINES

1 SHIFT, 6 HR WORKING, 3 YR PAYBACK, NPB

$0

$50,000

$100,000$150,000$200,000$250,000

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 

SQUARE FEET OF OTVC

$ / YEAR
Enclosed Machines Cost Le

Depending on Solvent Cos

• Depends on solvent price

• HFE - $15

COST OF SOLVENT DEGREASING MACHINES

1 SHIFT, 6 HR WORKING, 3 YR PAYBACK, HFE'S

$0

$50,000

$100,000$150,000$200,000$250,000$300,000$350,000$400,000$450,000

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45

SQUARE FEET OF OTVC

$ / YEAR

OTOOTOOTO
Enclosed Machines Cost Le

• Labor cost $13 / hr Waste disposal $350 

COST OF SOLVENT DEGREASING MACHINES

3 SHIFTS , 18 HR WORKING, TCE, 3 YR PAYBACK

$0

$50,000

$100,000$150,000$200,000$250,000

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 

SQUARE FEET OF OTVC

$ / YEAR

OTOTAIRAIRAIRAIR
Who Should Consider Buying 

Enclosed System

• Companies that:

• Have degreasers larger than 13 ft2 interface a

• Use designer solvents• Are located in a non-attainment areas• Have degreasers working more than 4 hours • Have heavy waste from process• Need to clean intricate parts or complex shap• Need flexibility in temperature• Have high labor costs and quality control 

requirements