Horizontal sidewall sprinklers are generally used in lieu pendent and upright sprinklers because of the building construction or installation economy considerations. They are designed for installation along a wall or the side of a beam and just beneath a smooth ceiling. Installed with their centreline of waterway horizontal, these sprinklers produce a quater-spherical water discharge patter that is predominately directed; however, a portion of the spray is also directed toward the back wall. Model FA001/FA002H, Standard/Quick Response Horizontal Sidewall Sprinklers, are automatic Sprinklers of the frangible bulb type and standard spray, 1/2” orifice, 5/3 mm bulb. They are standard/quick response – standard orifice sidewall sprinklers” intended for use in fire sprinkler systems designed in accordance with the standard installation rules recognized by the applicable Listing or approval agency (e.g., UL Listing is based on NFPA 13 requirements).