To assess the resistance of the surface of a fabric to wetting.
APPARATUS
1. Spray rating apparatus.
2. Set of AATCC rating photographs.
3. Five litre beaker.
TEST SPECIMENS
FABRIC
Three specimens, approximately 250mm x 250mm. avoid fabric within 50mm of selvedge and ensure that no two specimens contain the same set of warp and weft threads.
If the performance standard requires a spray rating both before and after washing, a further three 250mm x 250mm specimens, overlocked around the edge to prevent fraying, are washed and prepared as follows:-
1. Carry out the stability wash required by the appropriate performance standard in accordance with method of P1A ‘Washcator Stability Washes’ omitting the tumble dry procedure at this stage. The specimen should not be washed with any other fabric or garments, other than the standard make weights.
2. Rinse thoroughly in hand-hot natural tap water at 40⁰C ± 5⁰C in a litre beaker. DO NOT use artificially softened water.
3. Final rinse in cold distilled water.
4. Remove excess moisture with a paper towel.
5. Tumble dry in accordance with method of P1A ‘Washcator Stability Washes’.
CONDITIONING
Conditioned the prepared test specimen for a minimum of 4 hours in the standard atmosphere for testing, at a temperature of 20⁰C±2⁰C and a relative humidity of 65%±2%.
METHOD
1. Position the spray rating apparatus so that it is level. Check the levelness from front to back and from side to side, by using a spirit level.
2. Using a plumb line or a template ensure the distance between the canter of the specimens mounted on the ring holder is 152mm.
3. Pour 250ml distilled water into the funnel of the apparatus and check that the water is following freely through all the holes of the spray nozzle and that there is no leakage around the spray nozzle. Flow rate to be between 25-30 seconds.
4. Completely dry the outside surfaces of the apparatus with absorbent paper. It is particularly important to ensure that no drips remain the end of the nozzle.
5. Mount the specimen face up in the circular frame so that it is tout.
Locate the specimen holder such that the twills of gabardines piques and similar rib construction fabric are diagonal to the flow of water.
6. Locate the frame on the apparatus so that the specimen is mounted from top to base as it will be worn in the finished article. If this information is unknown, mount the specimen with the warp direction from top to base, if the sample is a pile fabric, the frame should be located so that the pile runs downwards.
7. Adjust the apparatus so that the face of the spray nozzle is 152mm above the centre of the specimen.
8. Measure 250ml of distilled water at 20⁰ ± 2⁰C and pour steadily but quickly into the funnel of the apparatus.
9. As soon as the spray ceases, before the last few ‘large droplets’ of water fall, remove the frame with the specimen on it, turn it face downwards and tap the edge firmly twice against a solid object, at an angle of 30⁰ (Approximately).
10. Assess the tested specimen immediately whilst it is still on the frame, using AATCC rating photographs.
11. If further specimen are to be tested it is imperative to dry the apparatus again as described in step 3, prior to testing each specimen.
RESULT
Report the following
1. Direction of test:
Fabric: Mounted warp top to base/weft Top to base.
2. Weather the specimen was Original/After Wash.
3. The wash given if applicable.
4. The AATCC grading (100 to 0) given for each specimen, when rating specimen as 0, the comments ‘upper and lower ‘ are referring to the areas of ‘face and back’ of the fabric.
Tags:
Textile