A resin joint includes a joint body having a flow path, sleeves, and union nuts that fix tubes to the joint body. The joint body has a body portion with a curved inner peripheral surface and a straight portion protruding from an end portion of the body portion. The straight portion has outer and inner cylindrical portions radially arranged inside the outer cylindrical portion. An end portion of the inner cylindrical portion is positioned closer to the body portion than is an end portion of the outer cylindrical portion. A groove portion extending parallel with the outer and inner cylindrical portions in an axial direction is formed between an inner peripheral surface of the outer cylindrical portion and an outer peripheral surface of the inner cylindrical portion. The tube is fixed to the joint body such that a press-fit portion of the sleeve is press-fitted in the groove portion.

A heating, ventilation, and air-conditioning (HVAC) duct system which includes, at least in part, one or more modular, uniform, pre-manufactured duct elbow elements having two faces of two sizes. Each elbow provides a twenty-two and a half degree (22.5°) bend in a duct system. When combined, the elbow sections can provide forty-five (45°) degree bends or ninety (90°) degree bends, or even offsets within a duct system. Due to the size and shape of the elbows, multiple elbows can be nested within one another for easy packing and shipping.

A heating, ventilation, and air-conditioning (HVAC) duct system which includes, at least in part, one or more modular, uniform, pre-manufactured duct elbow elements having two faces of two sizes. Each elbow provides a twenty-two and a half degree (22.5°) bend in a duct system. When combined, the elbow sections can provide forty-five (45°) degree bends or ninety (90°) degree bends, or even offsets within a duct system. Due to the size and shape of the elbows, multiple elbows can be nested within one another for easy packing and shipping.

A drainage device for an above-ground pool, and an above-ground pool including the drainage device are provided. The drainage device includes a drainage pipe, with inlet and outlet ends, and a drainage valve connected to the inlet end of the drainage pipe. The drainage valve includes a water inlet periphery, defining a water inlet in fluid communication with the inlet end of the drainage pipe, and a connecting member disposed circumferentially around the water inlet periphery. The connecting member is radially spaced apart from the water inlet periphery. The connecting member may be formed by injection molding around the water inlet periphery.

A sprinkler configured for engagement with a coupling, the sprinkler includes a raised lip end, the sprinkler defining a raised lip at the raised lip end; and a deflector end disposed opposite from the raised lip end, the sprinkler defining a groove between the raised lip and the deflector end.

A sprinkler configured for engagement with a coupling, the sprinkler includes a raised lip end, the sprinkler defining a raised lip at the raised lip end; and a deflector end disposed opposite from the raised lip end, the sprinkler defining a groove between the raised lip and the deflector end.

A resin joint includes a joint body having a flow path, sleeves, and union nuts that fix tubes to the joint body. The joint body has a body portion with a curved inner peripheral surface and a straight portion protruding from an end portion of the body portion. The straight portion has outer and inner cylindrical portions radially arranged inside the outer cylindrical portion. An end portion of the inner cylindrical portion is positioned closer to the body portion than is an end portion of the outer cylindrical portion. A groove portion extending parallel with the outer and inner cylindrical portions in an axial direction is formed between an inner peripheral surface of the outer cylindrical portion and an outer peripheral surface of the inner cylindrical portion. The tube is fixed to the joint body such that a press-fit portion of the sleeve is press-fitted in the groove portion.

A showerhead mounting pipe is provide for mounting a wall-mounted or ceiling-mounted showerhead. The pipe has two ends, and a bend of at least 45° between the ends. Each end of the pipe comprises a connector for a showerhead. The pipe is arranged to be cut at a selected location between the two ends so as to provide a suitable portion for use to mount a showerhead.

A fire protection system can include one or more pipes coupled with a fluid source, a pipe fitting coupled with the one or more pipes downstream of the fluid source, and at least one sprinkler coupled with the one or more pipes and the pipe fitting. The pipe fitting can include a wall defining an opening, the wall having an outer diameter, a first wall thickness at the opening, and a second wall thickness inward from the opening, the second wall thickness greater than the first wall thickness. The at least one sprinkler can be coupled with the one or more pipes and the pipe fitting to receive fluid from the fluid source through the one or more pipes and the pipe fitting.

A multi-conduit system has a joiner section comprising a plurality of conduits in parallel and a joining end for connection to a plurality of exposed like conduits of an adjacent section in use. The conduits of the section terminate at a proximal end of the joining end which comprises a collar widens in diameter from the conduits to form an open mouth. The collar defines an inner profile having a plurality of lobes having respective inner profiles corresponding to outer profiles of respective exposed like conduits such that, in use, when the like conduits of the adjacent section are inserted into the mouth, the lobes of the collar non-rotatably engage the like conduits to correctly align each conduit of the section with a respective like conduit of the adjacent section.