The Mine Safety & Health Administration (MSHA) is seeking to determine whether additional sources are available to provide respirable dust cassettes used by MSHA personnel to measure levels of dust exposure when conducting mine inspections.

The current dust cassette being utilized by MSHA is Mine Safety Appliances (MSA) Part # 10011208.  The following are some, but not all, of the specifications required for MSHA's dust cassettes:

Filter Media

The filter media should be a 5 micron, 37 mm diameter, non-hydroscopic polyvinyl chloride formulation. The filter resistance shall be not more than 2 inches of water at an air flow rate of 2 liters per minute. The aerosol retention per ASTM D2986-95A should be 99.9%+ for .3 micron dioctyl phthalate (DOP) at 32L/min/100cm2 of filter media. Air flow rates attainable at 10 psi should be approximately 53L/min/cm2 of filter area. The media should maintain these performance characteristics up to an ambient temperature of 125Fo.
A six digit cassette number and a bar code shall be imprinted on the back (non-sampling) side of the filter using indelible, fast drying ink. The filter shall have an ash content of less than 1% by weight, and neither the filter nor ink shall contain material which, after ashing or dissolution of the filter media, would interfere with the determination of silica by NIOSH Method 7500.

Filter Capsule

The removable capsule enclosing the filter should not permit sampled air to leak around the filter. It should be composed of non-hydroscopic material in the shape of a frustum, with a base diameter not to exceed 39 mm in diameter and a height not to exceed 4 mm. The top of the frustum shall be not less than 12 mm in diameter and shall be the site of the sample inlet port. The filter media and supports shall be sealed to the base of assembly, with the cassette number and bar code facing outward. The walls of the frustum should be constructed of aluminum foil to expedite recovery of the sample filters for silica analysis.
The weight of the capsule shall not exceed 5 g . Impact to the capsule should not dislodge sampled dust from the capsule which might be lost to the weight measurement. Capsules should be assembled in such a manner that the 99% confidence interval for weight stability of unused filters over a two year period is a weight change of between -30 micrograms to +60 micrograms.

Cassette

The cassette shall enclose the capsule so as to prevent leakage around the capsule and to prevent contamination. The cassette must be constructed so as to prevent a loss or gain in capsule weight during cassette assembly or disassembly. Appropriate covers shall be provided to seal the cassette when it is not in use, thus preventing contamination of the sample media and maintaining sample integrity.

 This is not a solicitation.  At the present, MSHA is only seeking vendors that have an interest in and can provide the product. 

Attached are several pictures of dust cassettes and components, and of the filter capsules with MSHA's robot accessories. 

Please respond to Rhonda Sizemore, Contracting Officer, at [email protected].  No phone calls please.  Deadline to respond is Tuesday, April 6, 2010 at 3:00 p.m. EST.