NIOSH 9111 SAMPLING TECHNIQUE
Method 1 Concentric Squares:
Used on hard surface such as glass, ceramic, tiles etc. Take the gauze out of the vial & unroll it to create a flat surface. Within the template window, using firm pressure, wipe in a clock wise direction from one of the corners of the inside of the template window working your way in to the middle (see diagram below – Fig 1.) Finishing with a scooping motion. Take the gauze & without touching anything else, fold the side you’ve just used to the inside & reveal a clean side. Again, using firm pressure wipe over the same area again in the same direction (see diagram Fig. 2) again finishing with a scooping motion. Fold the gauze again and place it back it the vial.
Method 2 – Side to Side:
Used on painted gib, pinex, smooth timber, etc. Take the gauze & unfold it to create a flat surface, then firmly wipe within the template in a side to side (zig zag) action, completing the action in at least 5 wipes, see Fig. 3 below. Finish with a scooping motion. Turn the used side to the inside, then wipe again in an up & down action completing the action in at least 5 wipes, (Fig.4) finishing with a scooping motion. Again fold the gauze to expose another clean surface & wipe again in a side to side action (Fig. 5) Fold the gauze & place it back in the vial.
Method 3 – Blotting:
Good for rough surfaces such as particle board and exposed timber. Take the gauze out of the vial and use a dabbing motion. Dab the gauze on to the surface within the template window, lift the gauze then dab to the right slightly overlapping as you go. Do this at least 5 times within the window of the template until your reach the right hand side. Dab just underneath your last dab & move to the left in the same manner zig-zagging your way to the bottom of the template window as per Fig. 6. Once at the bottom fold the used side to the inside, exposing a clean surface then begin dabbing from the top left of the window to the bottom left of the window and use the same zig-zagging overlapping method as before (Fig. 7) Again use a minimum of 5 dabs per line until you reach the right side of the template. Fold the gauze again & place it back in the vial.
The report you will receive back from the laboratories will show the result in ug/sample and not in ug/100cm2.
Note: (Detailed Test) (Post decontamination)
- Use new gloves each sample you take to reduce the possibility of cross contamination.
- Take one sample for every 10m2 of the floor space in a room or part thereof
- If you are taking sample on varnished surface, heat pumps, vent etc. Take another one from a lower contaminated area
- If you are taking sample on wallpaper, bare plasterboard, concrete, bare timber etc. take another sample in an area where contamination may be higher.
- Field blank – 1 in every 20 samples