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A4OM 3 PRELIMINARY PROCEDURES Prior to mobilizing to install Sub-slab monitoring probes(SSMPs)or Sub-slab Vapor Pins& • Verify access has been granted for the building in question for the period necessary for installation and sampling. 3.1 UTILITIES • Review surrounding features (e.g. drains, meters)to determine where utilities are entering the building. The owner of the building should also be consulted for their knowledge of any additional known utilities. • Check to see what utilities may be present within or beneath the building slab. • Procure as-built drawings, if possible. Identify sinks, commodes, drains and any other evidence of subsurface utilities. • Geophysical methods(e.g., ground penetrating radar)can be used to assist in locating utility lines. 3.2 MOBILIZATION Mobilize equipment into the location, minimizing re-entries, and perform the following: • Verify that screening instruments are operating properly. Instruments indicating negative concentrations will be re- zeroed. • In the room where a SSMP or Vapor Pin® is to be installed,assess indoor air quality using a four gas meter, methane detector, and PID, If readings are elevated (above baseline); locate sources that may be contributing to the elevated readings. • If VOCs or LEL readings are above the action levels per the Health and Safety Plan (HASP),work will cease until ambient air conditions have resumed safe levels. 4 INSTALLATION PROCEDURES Collect sub-slab soil-gas samples at up to six locations per building of interest(or as otherwise defined in project planning documents). Collect sub-slab soil-gas samples at specified locations. • Adjust the locations as needed to account for logistical factors. • Select an area where visible damage to the floor will be minimized. • Select areas with floor penetrations (i.e. bathrooms, kitchens). 4.1 SAMPLING PROBE CONSTRUCTION—VAPOR PIN® Obtain stainless steel tubing from Swagelok®(e.g., Swagelok 6L-T4-S-035-20, in 20 ft lengths at roughly$5/ft). If possible, pre-cut the 1/8"stainless steel tubing before deploying to the field and bring a variety of lengths(e.g.4",6", 12"). • Select a length of stainless steel tubing so that the bottom of the probe is close to the bottom of the sub-slab (typically a 4"probe for a 6"sub-slab). • Attach the reducer via a port connector, to establish the sample train configuration. Attach a 2 to 3 ft. length of Teflon or polyethylene tubing to the other end of the union. Put a 1/4 nut at the end of the tubing and use a plug (what Swagelok®calls a cap)to seal the system and prevent air flow in or out of the sub slab while the probe sits idle. Or Obtain brass,stainless steel, or FLX-VPTM Vapor Pin® sampling device,Tygon connectors,Vapor Pin® sleeves, and flush mount covers from a vendor. 4.2 SAMPLING PROBE CONSTRUCTION Obtain stainless steel tubing from Swagelok®(e.g., Swagelok 6L-T4-S-035-20, in 20 ft lengths at roughly$5/ft). If possible, pre-cut the 1/8"stainless steel tubing before deploying to the field and bring a variety of lengths(e.g.4", 6", 12"). • Select a length of stainless steel tubing so that the bottom of the probe is close to the bottom of the sub-slab (typically a 4"probe for a 6"sub-slab). • Attach the reducer via a port connector, to establish the sample train configuration. Attach a 2 to 3 ft. length of Teflon or polyethylene tubing to the other end of the union. Put a 1/4 nut at the end of the tubing and use a plug (what Swagelok®calls a cap)to seal the system and prevent air flow in or out of the sub slab while the probe sits idle. Drill down into the slab approximately 1 to 2 inches using a rotary hammer drill with a 7/8"diameter concrete bit.