Abstract: A negative pressure control system for protection from airborne asbestos particles, gases and the like from a work space includes an enclosure formed of portable rigid doorway panels and doors with transoms communicating with the work space and defining an air intake and decontamination chambers, an exhaust unit having a blower and HEPA filter is positioned in the work space and discharges to the atmosphere and maintains a suitable negative air pressure in the work space and a substantial flow of air through the work space and the decontamination chambers. The enclosure may comprise a room divider and/or a temporary room in communication with the work space. The doors are normally closed as by spring action and the transom closures open responsive to air flow towards the work space and closes with the loss of negative air pressure within the work space.

Abstract: A reflex light reflector comprising a laminate of water-insoluble layers including an internal specular-reflecting metal layer sealed between water-insoluble layers and formed in situ by vapor deposition of metal to a sufficient thickness to constitute a continuous opaque electrically conductive film, and a monolayer of microsphere lens elements of a diameter within the range of 10 to 200 microns overlying the metal layer and bonded by resinous bonding material in optical relationship thereto for reflex light reflection, wherein said metal layer is characterized by being multiply fractured in a random pattern resembling the cracking pattern of a dried mud flat such that it consists of a multiplicity of non-overlapping patches of metal, each fractionally separated from others sufficiently to render said metal layer highly resistant to electrolytic corrosion, each said patch having an area size sufficient to underlie from one up to about thirty of said lens elements, with each said patch having at least one dep

Abstract: An elastic joint-spanning waterstop of particular design for use in a method of sealing joints, in particular expansion joints between concrete sections in roads, bridge and parking deck structures against passage of water, dirt, etc., is described. In the method, recesses are formed in the concrete surface on each side of the joint and the specially designed flexible elastic joint-spanning waterstop element is placed therein, and thereafter a layer of rigid-setting grout is then placed over the element. The waterstop element is in the form of a continuous strip having in cross-section a center portion for location in the joint, and lateral joint-spanning web portions. The webs have a number of openings therethrough to admit fluid grout therein. An upstanding rib is placed between the openings and the center section and is spaced therefrom.

Abstract: A method of sealing joints e.g. between concrete sections in road, bridge and parking deck structures against passage of water, dirt, etc., is described wherein recesses are formed in the concrete surface on each side of the joint and a specifically designed flexible elastic joint-spanning strip having openings therethrough is placed therein. A layer of rigid-setting grout is then placed over the strip, the openings in the strip when filled with grout serving to support the upper layer of grout and to prevent flexing and cracking thereof by vehicle traffic passing thereover, as well as to anchor the strip to the concrete bodies.