1, building drainage systems division 1), according to the design flow state divided: (1) semi-pressurized flow (87 bucket) stormwater system. Refers to the use of 65-type, 87 water bucket system design flow pattern is semi-pressurized fluidized, traffic load of the system, piping and other considerations of the role of water pressure. Widely used in China at present. (2) the pressure flow (siphon) drainage systems. A form of roof drainage is the use of water bucket under design conditions to the discharge pipe difference between the effective power, creating a negative pressure within the system so that rainwater drainage system, the hydraulic fluid dynamics calculated on the basis of Bernoulli equation. (3) gravity flow (weir bucket) drainage systems. Refers to the use of free-flow water bucket weir system design flow state is free flow state, the traffic load of the system, piping, etc. ignore the role of water pressure. Widely used in China at present. It is a relatively new product. 2) divided by the pipeline installation position: in the drainage system and external drainage systems. 3), according to the roof drainage conditions point: gutters drain, gutter drainage and no drainage ditch. 4) Press the household cross pipe (drainage) in the indoor section if there is free water surface divided: Closed systems and open systems. 2, features a variety of roof rainwater systems systematically Category Features 87-bucket siphon weir bucket design flowing water mixed gas stream (consider pressure) water-phase flow (consider pressure) mural film stream (without regard to pressure) water bucket in the form of 87 or 65 type siphon water submerged weir free flow pipeline design data mainly from the experimental formula formulas calculate the design return period greatly exceed the value of small design return period rainfall exclude troubleshoot system itself, designed with drain excess rainwater overflow realized primarily through the design of the head of state have taken full advantage, excess water can no longer enter through the overflow to achieve necessary, the system design without pressure, excess water enters creates pressure, damaging the roof overflow system frequency Small pipe consumption greatly toll system between the two after the calculation between simple, rough accurate, complex simple plugging on the upstream tube No No leaks or rupture may 3, select building rainwater systems Principle 1), Select rainwater system should be quickly and timely manner to the outside row of roof rainwater ground or conduit. Roof rainwater refers to the design life of the building is less than the return period rainfall. 2) the principle of a safe and economical alternative systems. Security implications include: indoor floor not to take water, roofing overflow low frequency, watertight pipes to take water. Economy means: to meet the premise of security, systems low cost, long life. 3), industrial buildings and roof floor pan of water to take water gave our factory causing huge economic losses. Rainwater from the roof is non-normal overflow outlet overflow drainage, should be minimized or avoided. 4) Since the 1980s, industrial and civil roofing overflow occurs rarely, should not be easily increased frequency selection rainwater overflow system. Selection 1), according to the size of the security of each rainwater systems in order of precedence 4, building drainage systems order: Closed System → open drainage system outside the system 87 → fight gravity flow drainage system siphon system → system → Weir Flow fighting gravity flow system (with roof overflow frequency as the main factor). 2), according to the economic advantages and disadvantages of each system of rainwater The order is: Siphon System → 87 fighting gravity flow system → weir fighting gravity flow system. 5, the construction, installation points 1), water bucket installed by roofing materials of construction to take different installation methods, in accordance with the National Building Standard Design Atlas 01S302 "water bucket" selection. The key requirement is to prevent leakage, waterproofing membrane waterproofing methods are pressing, welding to riveting clamp packing etc. 2), pipeline installation (1) HDPE pipeline installation using special hangers and riser card to cover the pipeline load, prevent pipe sway control pipeline axial stretching. Fusion welding or welded pipes are connected to the hoop. General installation steps: Step one: put the line in the building and find a suitable suspension point; the second step: the installation sheet and the suspension rods mounted on the building; the third step: in the ground will square steel rails and control cards are fitted together; Step 4: assembled suspension system suspended from the boom; Step five: the pipeline installation to the control card. (2) steel or stainless steel tube stainless steel tube of the Union or argon arc welding, welding, soldering required by the relevant specifications. Steel pipe card can be used plaque or circular steel cards, hanger, see the National Building Standard Design Atlas 02S402 "pipe supports and hangers." Buttress bottom of the riser should be located. Pipe support spacing Press "Building Water and Systems Engineering Construction Quality Acceptance" GB50252-2002 execution. 6. Implementation of standards 1), engineering standards "building water supply and drainage design specifications" GB 50015-2003 "building and rainwater utilization project technical specifications" GB 50400-2006 "Building Water and Heating Engineering Construction Quality Acceptance" GB50242-2002 2 ), the relevant standard drawing 01S302 "water bucket" 03S402 "interior pipe supports and hangers"