Abstract: An air flow filter device includes a housing having at least two openings therein, a stationary air filter, such as an HEPA filter, disposed within the housing, and a one-way air flow valve disposed within the housing in parallel with the filter. The valve is positioned such that sufficient air flowing into the housing from the one opening closes the valve so that such air flows through the filter in order to exit through the other opening, and such that sufficient air entering the housing from the other opening opens the valve so that the air flows through the valve in order to exit through the one opening. In this manner, air may be circulated in both directions without escape of contaminants, such as asbestos fibers, into the environment.

Abstract: The liquid impervious liner in a field erected liquid holding tank that can be dismantled and reassembled is protected from damage by placing a reusable liner buffer in the form of a blanket of load spreading, cushioning material between the liner and the wall of the tank and the ground or tank foundation. Methods of erecting tanks using liner buffers to protect liquid holding liners are disclosed.

Abstract: An improved storage apparatus for dry material in bulk is disclosed. The storage apparatus includes a tarpaulin cover and a circular metal wall. The tarpaulin cover is secured to the circular metal wall, or to any suitable surface, by a lashing means including a plurality of eyelets in the periphery of the tarpaulin cover, a plurality of anchors attached to the wall or, alternatively, to any suitable surface, a first cable attached to the anchors so as to encircle the wall, and a second cable alternately threaded through the eyelets and around the first cable.According to another embodiment there is provided a storage container which includes a flexible membrane cover and a flexible membrane base. Alternatively, the flexible membrane cover is provided separately for a pile of dry material in bulk. In these embodiments the flexible membrane cover is secured to any suitable surface utilizing the lashing means described above.