1. (1) A minimum of two samples shall be taken outside the regulated abatement work area, within 10 feet of the isolation or critical barriers. When positive pressurized HVAC ducts are located within the regulated abatement work area, one of these samples shall be collected within 10 feet of an HVAC diffuser, at the downstream side of the positive pressurized HVAC ducts, in adjoining non-work areas. Where the entire building/structure is the regulated abatement work area, an additional exterior ambient air sample, remote from that in paragraph (3) of this subdivision shall be taken.
2. (2) A minimum of one sample shall be taken outside the regulated abatement work area, within 10 feet of and within proximity to each entrance or exit from the regulated abatement work area.
3. (3) One ambient air sample shall be taken outside the building or structure within 25 feet of the building or structure.
4. (4) Once the negative air systems have been established, one sample shall be taken in front of and within 10 feet of each unobstructed, negative pressure ventilation equipment exhaust or bank (grouping of not more than five exhaust ports at one termination area) of exhausts but not within a duct itself.
5. (5) Once the negative air systems have been established, where negative ventilation unit exhaust ducts run through the non-work area portions of building or structure to access the exterior, one sample shall be collected in the building or structure, within 10 feet of the duct system.

6. (6) If remote decontamination units are used, one sample shall be collected at each entrance/exit from each personal decontamination and waste decontamination enclosure.

   (d) Work stoppage criteria during Phase II A abatement procedures.

   If air samples collected outside the regulated abatement work area, indicate airborne fiber concentrations at or above 0.01 fiber per cubic centimeter, or the established background level, whichever is greater, work shall stop immediately for inspection and repair of barriers and negative air ventilation systems as necessary. Clean up of surfaces outside of the regulated abatement work area using HEPA-vacuums and wet-cleaning methods shall be performed prior to resumption of work area preparation activities. A summary of clean up activities and the results of barrier inspections including any necessary repairs, shall be documented in the supervisor's daily project log. Work methods shall be altered accordingly to reduce fiber concentrations to acceptable levels. No ACM, PACM or asbestos material shall be disturbed during Phase II A activities.

(a) Personal air sampling.

Air sampling shall be performed in the worker's breathing zone, by the asbestos contractor for his personnel, as required by current OSHA regulations.

(b) Daily air sampling.

Project air sampling shall be conducted daily for the full workshift, for all large size projects with OSHA Class I or OSHA Class II friable ACM subject to handling/abatement. (See Table 2 within section 56-4.9 of this Part.) If more than one daily workshift is required to accomplish the work, air sampling shall be performed on each workshift. Air sampling is not required on days when there are no Phase II A activities.

(c) Number and location of samples - large asbestos projects.

A minimum of five samples shall be taken on a daily basis. The location of samples to be taken are as follows: