Leader heads or conductor heads [1] are funnel-shaped components of a roof drainage system connected in most cases to a gutter and to a downspout. [2] The system conveys water from the roof that is collected in the gutters to the ground or into a storm water management system.
The purpose of a leader head is to help transfer excess water from the roof onto downspouts, thus preventing the gutters from overflowing and water washing over the walls, which is a common occurrence in areas susceptible to heavy rain cycles. The use of leader heads also offers other benefits to the drainage system. Because the top of the funnel is open, air is constantly introduced into the system and water flows faster through the downspouts. Additionally, some leader heads are designed to receive more than one downspout, or in some cases more than one gutter converge onto a single leader head. Leader heads have historically provided an opportunity to incorporate a decorative element within their design. These elements, as are the other roof drainage system components, gutters, scuppers [3] [4] or downspouts, have to be sized to perform well, according to the amount of precipitation that they are intended to help alleviate.
Leader heads can also receive water from scuppers, which are used predominantly through flat roofs’ parapets. In those cases, the leader head provides the transition from scupper to downspout.
Leader heads can be incorporated into a rain water harvesting system, by helping direct the water into collection cisterns. This way, the harvested natural resource, rainwater, can be redistributed as best fits the needs. Whether the leader head fits directly into the collecting tank, or is connected to a down pipe first, contaminants and debris such as such as leaves, twigs from trees, and bird and other animal droppings among others, must be kept out of the tanks. For this purpose leaf guards or leaf diverters are very useful, since they are simple angled screens installed in such manner as to deflect leaves and debris while allowing water to pass through.
In Australia a leader head is known as a Rainhead.
Leader heads have their origin in the gargoyles of Romanesque and Gothic buildings. Over time they have been redesigned to fit stylistic building trends, their function has always remained a constant.
Today, leader heads are typically made of sheet metal materials such as copper, steel, aluminum, zinc or brass, or cast materials such as aluminum; historically they were made of lead, copper, or cast iron. Leader heads are also made in different sizes and shapes such as square, round, hexagonal, etc.
2018 International Plumbing Code [5] | CHAPTER 11
Section 1106 Size of Conductors, Leaders and Storm Drains
(See associates tables 1106.3 & 1106.6 included in the respective sub-sections)
2018 International Building Code [6] | SECTION 1502 ROOF DRAINAGE
ASTM STANDARDS
A roof is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temperature, and wind. A roof is part of the building envelope.
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delivery are among the most common uses for plumbing, but it is not limited to these applications. The word derives from the Latin for lead, plumbum, as the first effective pipes used in the Roman era were lead pipes.
In architecture, and specifically Gothic architecture, a gargoyle is a carved or formed grotesque with a spout designed to convey water from a roof and away from the side of a building, thereby preventing it from running down masonry walls and eroding the mortar between. Architects often used multiple gargoyles on a building to divide the flow of rainwater off the roof to minimize potential damage from rainstorms. A trough is cut in the back of the gargoyle and rainwater typically exits through the open mouth. Gargoyles are usually elongated fantastical animals because their length determines how far water is directed from the wall. When Gothic flying buttresses were used, aqueducts were sometimes cut into the buttress to divert water over the aisle walls.
A storm drain, storm sewer, highway drain, surface water drain/sewer, or stormwater drain is infrastructure designed to drain excess rain and ground water from impervious surfaces such as paved streets, car parks, parking lots, footpaths, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems.
A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. Especially in residential buildings, it often is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, car park, and air-conditioning system are located; so also are amenities such as the electrical system and cable television distribution point. In cities with high property prices, such as London, basements are often fitted out to a high standard and used as living space.
A drain-waste-vent system is the combination of pipes and plumbing fittings that captures sewage and greywater within a structure and routes it toward a water treatment system. It includes venting to the exterior environment to prevent a vacuum from forming and impeding fixtures such as sinks, showers, and toilets from draining freely, and employs water-filled traps to block dangerous sewer gasses from entering a plumbed structure.
A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The U.S.-based National Roofing Contractors Association defines a low-slope roof as having a slope of 3 in 12 (1:4) or less.
The eaves are the edges of the roof which overhang the face of a wall and, normally, project beyond the side of a building. The eaves form an overhang to throw water clear of the walls and may be highly decorated as part of an architectural style, such as the Chinese dougong bracket systems.
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; a hollow pipe is far stiffer per unit weight than the solid members.
A rainwater tank is a water tank used to collect and store rain water runoff, typically from rooftops via pipes. Rainwater tanks are devices for collecting and maintaining harvested rain. A rainwater catchment or collection system can yield 1,000 litres (260 US gal) of water from 1 cm (0.4 in) of rain on a 100 m2 (1,100 sq ft) roof.
A rain gutter, eavestrough, eaves-shoot or surface water collection channel is a component of a water discharge system for a building. It is necessary to prevent water dripping or flowing off roofs in an uncontrolled manner for several reasons: to prevent it damaging the walls, drenching persons standing below or entering the building, and to direct the water to a suitable disposal site where it will not damage the foundations of the building. In the case of a flat roof, removal of water is essential to prevent water ingress and to prevent a build-up of excessive weight.
Basement waterproofing involves techniques and materials used to prevent water from penetrating the basement of a house or a building. Waterproofing a basement that is below ground level can require the application of sealant materials, the installation of drains and sump pumps, and more.
Metals used for architectural purposes include lead, for water pipes, roofing, and windows; tin, formed into tinplate; zinc, copper and aluminium, in a range of applications including roofing and decoration; and iron, which has structural and other uses in the form of cast iron or wrought iron, or made into steel. Metal alloys used in building include bronze ; brass ; monel metal and nickel silver, mainly consisting of nickel and copper; and stainless steel, with important components of nickel and chromium.
A downspout, waterspout, downpipe, drain spout, drainpipe, roof drain pipe, rone or leader is a pipe for carrying rainwater from a rain gutter.
A box gutter, internal gutter, parallel gutter, or trough gutter is a rain gutter on a roof usually rectangular in shape; it may be lined with EPDM rubber, metal, asphalt, or roofing felt, and may be concealed behind a parapet or the eaves, or in a roof valley.
The International Plumbing Code is a plumbing code and standard that sets minimum requirements for plumbing systems in their design and function, and which sets out rules for the acceptance of new plumbing-related technologies. It is published by the International Code Council based in Washington, D.C., through the governmental consensus process and updated on a three-year cycle to include the latest advances in technology and safest plumbing practices. The current version of this code is the 2021 edition. The IPC protects public health and safety in buildings for all water and wastewater related design, installation and inspection by providing minimum safeguards for plumbers and people at homes, schools and workplaces. Water heaters, anti-scalding devices, back-flow prevention methods, water pipe sizing and many other such issues are addressed in the IPC.
Copper tubing is available in two basic types of tube—plumbing tube and air conditioning/refrigeration (ACR) tube, and in both drawn (hard) and annealed (soft) tempers. Because of its high level of corrosion resistance, it is used for water distribution systems, oil fuel transfer lines, non-flammable medical-gas systems, and as a refrigerant line in HVAC systems. Copper tubing is joined using flare connection, compression connection, pressed connection, or solder.
In civil engineering, ponding is the (typically) unwanted pooling of water, typically on a flat roof or roadway. Ponding water accelerates the deterioration of many materials, including seam adhesives in single-ply roof systems, steel equipment supports, and particularly roofing asphalt. On low-slope asphalt roofs, ponding water allows the oil solvent components of the asphalt to leach out and evaporate, leaving the roof membrane brittle and susceptible to cracking and leaking in the ponding location. The time taken for water to saturate a zone, usually from rainfall, causing a pond to form, is referred to as the "ponding time"
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Copper has earned a respected place in the related fields of architecture, building construction, and interior design. From cathedrals to castles and from homes to offices, copper is used for a variety of architectural elements, including roofs, flashings, gutters, downspouts, domes, spires, vaults, wall cladding, and building expansion joints.
A butterfly roof is a form of roof characterised by an inversion of a standard roof form, with two roof surfaces sloping down from opposing edges to a valley near the middle of the roof. It is so called because its shape resembles a butterfly's wings.
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