Housings Shall be per Massachusetts Highway Department (MHD) specifications and on their current approved list. Housings shall be of die-cast aluminum alloy or polycarbonate, rigidly constructed, and with a smooth outer surface. Housings shall be constructed to hold securely in place the optical units hereinafter described. Each housing shall be adaptable for post-top, bracket or rigid mast-arm vertical mounting. Assembled housings shall be dust and moisture proof. Each housing shall be equipped with doors of die-cast aluminum or polycarbonate. Each door shall be designed to hold the lens and shall be hinged and fastened by a wing nut or nuts of corrosion resistant material or equivalent to insure uniform pressure around door frame. Each lens shall be provided with a one piece neoprene gasket to cushion and seal lens inside and outside. Weather-resisting, mildew-proof gasketing shall be provided between the body of the housing and each door. Housings shall be provided with attached tunnel visors. Full circle visors are not acceptable. The assembled housings shall be made up of individual sections fastened together in a satisfactory mechanical manner. The assembly of three or more sectional units shall present a smooth unbroken contour of pleasing appearance. Each end of the housing assembly shall have an opening for the slip fit of a 1 1/2 inch pipe nipple. The area around this opening shall be reinforced and shall have integrally die-cast locking notches to provide positive signal positioning and insure against head rotation. Attachment to a slip fitter shall be made with a 1 1/2 inch pipe nipple and locknuts that match the integrally die-cast notches in the housing. Multiple-way housings are to be assembled by grouping one-way housings on suitable arms to form the required number of adjustable signals. The individual oneway housings are to be attached to arms of suitable length to permit free rotation of the housings without interference so that they may be aimed in any desired direction and locked securely in place. All bracket arms shall consist of one and one half (1 1/2") inch galvanized pipe with threaded ends and one and one half (1 1/2") galvanized rail fittings. Rail fittings on bottom bracket arms shall have threaded caps for wiring access. With each assembled one-way housing, there shall be supplied one ornamental cap; such cap when used, is to act as a cover over the hole in the top section and is to be of such design that no water may enter the housing. Slip Fitters Slip fitters shall be of malleable iron, strongly constructed, and of hollow design to permit the carrying of wires from the housing to the post or arm without their exposure at any point. Slip fitters must be of such character as to permit free adjustment and locking of the housings in the desired horizontal position. Each slip fitter shall be of such design that it will slip over a male projection on the top of the post, the diameter of this projection being the same as the outside diameter of a four t4) inch pipe and not less than four (4) inches long and the slip fitter being adjusted by means of 3/8 inch square head, cup point, anodized steel set screws. Slip fitters will not be required unless specified in the purchase order. Painting All exposed metallic parts of housings or of slip fitters must have at least two coats of enamel paint. Color code to be as follows: Option #1: Housings: Back --- Black Front --- Black Visors: Outside --- Black Inside --- Dull Black Bracket & Arm Assemblies: --- Black Option #2: Housings: Back --- Yellow Front Housing Door --- Black Visors: Outside --- Yellow Inside --- Dull Black Bracket & Arm Assemblies: --- Yellow The option to be used for a particular project will generally be specified on the plans or in the special provisions. If the option is not defined, the contractor shall request direction from the BTD Engineer.
