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Trial Number 0

Client Number 314

Project Number 1

Trial Purpose:

To evaluate supplied products for Green Seal GS 34 degreasing standard.

Date Run:

12/11/2008

Experiment Procedure:

According to Green Seal, GS 34 is a procedure for evaluating the ability of a degreaser to remove soil and is based on ASTM G-122, (1996), MIL-PRF-87937C (DOD, 1997) and MIL-C-
29602 (DOD, 1995).

Two types of soils were prepared individually. The first soil, maintenance soil, consisted of 10 grams of carbon black, 10 grams iron oxide, 100 ml WD-40, 100 ml hydraulic oil, and 100 ml gear oil. Each component was placed in a 750 beaker and mixed for 20 minutes at room temperature using a magnetic stirrer. The second soil, production soil, was made by mixing 200 ml Quench Oil and 200 ml cutting oil for 20 minutes at room temperature using a magnetic stirrer in a second 750 ml beaker.

Approximately 100 mg of each soil was applied to a precleaned and preweighed stainless steel coupon onto one side only with a handheld swab. No soil was applied to the two control coupons. The maintenance soil for all three coupons was baked in an oven for 30 minutes at a temperature of 40° C (105 F). For the production soil, all three coupons were baked in an oven for thirty minutes at 105° C (220 F). The coupons were then allowed to cool to room temperature and weigh a second time (soiled mass = B).

One cleaning product was diluted to 5% and was used at 100%. The solutions were preheated to 40 C (105 F). Four 600 mL beakers were filled with enough fresh degreaser solution to completely submerge the coupons in the degreasing solution without any overflow. The four beakers were suspended in the heated tank and allowing the temperature in the cleaning bath and beakers to equilibrate.

Each coupon was suspended in a beaker, allowing the entire contaminated surface to be submerged in the cleaning solution. The coupons were washed for 20 minutes using immersion cleaning only.

The washing was followed by two rinse steps. The coupons were drained for 30 seconds prior to each rinse step. For each rinse step a 20 minute soak was utilized. After the two rinse steps, all coupons were first allowed to air dry for 30 minutes and then dried in an oven at 105° C for 30 minutes. The coupons were then cooled to room temperature and final weights were measured (mass of the coupon after cleaning = C).

The control coupons were examined to determine if there were any visible signs of corrosion. Next, the control coupon was weighed to determine if there was any lost mass, which might occur if corrosion was in progress; or gained mass, which might occur if the degreaser had left a residue on the coupons. The following equation was applied:
[MCC - MCB] < 0.1 mg (which is the maximum balance error).
Where:
MCC = mass of the control coupon after washing and rinsing
MCB = mass of the control coupon before washing and rinsing

For the cleaned coupons, the amount of residual soil per surface area was calculated, using the following formula:
RS = (C-A)/ Ar
Where:
RS = amount of residual soil (mg/m2)
C = mass of the coupon after cleaning
A = initial coupon mass
Ar = surface area = 0.0035 m2

If the average residual maintenance soil loading, and the average residual performance soil loading are each less than 2,000 mg/m2, the degreaser meets the cleaning performance criteria.

Trial Results:

The supplied cleaning product was successful at both concentrations in removing the maintenance soil and the process soil using immersion cleaning at 105F. Both soil cleaning had residual soil levels under the 2000 mg/m2 level. Efficiencies were calculated to be in the table lists the weights of the coupons and the calculated RS values.

STC 300 Degreaser - 5%

Coupon Initial mass of coupons -g (A) Mass of coupon after - g soiling (B) Mass of coupon after - g cleaning (C) Residual soil (mg/m2)  Mass difference control (mg)
M1 62.5021 62.6079 62.5089 1700 -
M2 62.7552 62.8466 62.7600 1200 -
M3 62.7803 62.8913 62.7818 375 -
MC   64.1101 64.1100 - 0.1000
Average       1092  
P1 63.8066 63.8969 63.8069 75 -
P2 62.841 62.9507 62.8419 225 -
P3 59.2956 59.3994 59.2959 75 -
PC   63.0445 63.0444 - 0.1000
Average       125  

STC 300 Degreaser - 100%

Coupon Initial mass of coupons -g (A) Mass of coupon after - g soiling (B) Mass of coupon after - g cleaning (C) Residual soil (mg/m2)  Mass difference control (mg)
M1 62.7283 62.8340 62.7286 75 -
M2 62.691 62.7982 62.6921 275 -
M3 62.8281 62.9342 62.8281 0 -
MC   61.3451 61.3452 - 0.1000
Average       117  
P1 60.189 60.2886 60.1898 200 -
P2 63.7859 63.8894 63.7869 250 -
P3 62.5819 62.6881 62.5827 200 -
PC   64.0697 64.0698 - 0.1000
Average       217  

Success Rating:

A follow up test, usually based on company input.

Conclusion:

The supplied cleaning product at either dilution was success for the two soils and would meet the Green Seal GS 34 requirement of an average of 2000 mg/m2 for both soils using immersion cleaning. The same product will be evaluated for oil-water separation.

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