It covered installation and removal of filters during sampling and warned that "this SOP must be considered as provisional because experience with the B-S7B unit in the field does not exist 18 His instructions ran as follows: 1.0 Materials, tools, vehicles, and personnel required. 1.1 Materials, Pre-cut filter paper for F-8,G and B-57B filter units, aircraft safety wire, 36 inch roll heavy wrapping paper. 1,2, Tools. 1,.2,1 Assembly tools, 1.2.2 Side cutters, long-nosed pliers. Removal tools, Long-handled side cutters, 9 foot removal pole, long-handled tongs, long-handled wire puller, long-handled paper roller tool, longhandled instrument adjusting tool, long~handled hooked carrying pole for filter paper containers, box shielded with 1/l inch lead sheet for empty filter holder scrap tie wire, rack for removal tools, shielded V shaped "cave" for rolling filters, shielded filter paper carrying cases (pigs). 1.3 Vehicles, Two (2) low bed, rubber-tired trailers, in tandem towed by truck or tug; one (1) low bed, rubber- tired trailer pulled by truck or tug, 1h Personnel, Two (2) airmen, one (1) officer for direct removal operations, plus one (1) overall supervisor. 2.0 Assembly and Installation. 2el Assembly. 2.1.1 --- Pre-cut filter is laid into clean filter holders with care taken to assure good overlap of frame edges by filter material, Caution: Cloth scrim mst be laid next to small mesh (din.) wire of aft frame of holder; reject filters which have badly ravelled or separated scrim at edges. Holder is then closed and safety-wired as required, Caution: Hands and working surfaces must be surgically clean to avoid undesirable contamination of filter materials during preparation, Holders should be identified by 220 APOHO SWEH-2-0034 ro! c oweyr