Any roofing system’s integrity and functionality depend on knowing how to calculate funnels for internal drainage. These parts are vital but sometimes disregarded; they are crucial in keeping rainwater off the roof, avoiding water damage, and extending the life of the building.
Internal drainage funnels, sometimes referred to as roof drains or scuppers, are made to effectively direct melted snow or rainwater into the building’s drainage system. By carefully calculating the amount of water that these funnels should be able to hold during heavy downpours without overflowing, the stability and safety of the entire roofing system is guaranteed.
The computation process takes into account a number of important variables, such as the surface area of the roof, the average intensity of rainfall in the area, and the intended drainage efficiency. Roofing experts can precisely measure these factors to ascertain the ideal quantity, dimensions, and positioning of drainage funnels required to efficiently control water flow.
Internal drainage funnel design is also influenced by local building codes, material type, and roof slope. Ensuring adherence to these regulations guarantees legal observance in construction practices and safety, in addition to improving the system’s performance.
- Internal cold and hot water supply systems
- Calculation of internal drains
- Video on the topic
- Roof repair with funny replacement
- Marking and preparation of holes for the AquasyStem germinal funnel
- Simple calculation of cone deployment
- RIM-DRaintrace-Kit ready-made solution for heating the funnels of the internal drainage
- The main and emergency drainage of the flat roof SITA (Germany) | video instruction calculation of drainage
- Drainage funnels with heating and without. Choice, rule of installation on a flat roof.
- The device of the internal drain funnel
- Training video. 8. The funnels of the inner gutters. Device of flat roofs Technonikol
Internal cold and hot water supply systems
20. Drains inside the body
20.1. Rain and melted water from building roofs should be removed by internal drains.
Note: When setting up internal drains in buildings without heating, precautions should be taken to ensure that drainage funnels and pipelines are kept at a temperature that is lower than that of the surrounding air (e.g., by using steam heating or electric heating). Mathematical and technical calculations should be used to support the device of heated internal drains.
20.2: Rain or public sewage should be the destination for water that exits interior drains.
Notes: 1. Water from the internal gutter system may be supplied to the production sewage system of non-trampled or repurposed wastewater when it is deemed necessary.
2. Connecting the internal drain system of sanitary devices to household sewers and draining water from internal drains to them is prohibited.
20.3. When rainwater from internal drains is not being used for sewage, it should be collected openly into trays close to the building (open production); in this situation, precautions should be taken to prevent soil erosion near the building.
Note: In the winter months, a hydraulic shutter with meltwater diverts should be installed in a home sewer when installing an open output on the riser inside the building.
20.4. At least two drainage funnels must be installed in one yendov and on the building’s flat roof.
The location of roofing funnels on a roof should take into account the building’s structure, the allowed area for the water column in each funnel, and the relief of the roof.
For any kind of roof, the maximum separation between drainage funnels shouldn’t be more than 48 meters.
Note: One drainage funnel per section may be installed on flat roofs of public and residential buildings.
20.5. If the riser’s total computed flow rate does not surpass the values listed in the table, connecting one riser of funnels situated at various levels is permissible. 10.
Drainage riser diameter, in millimeters
20.6. In compliance with section requirements, the minimum slopes for the withdrawal pipelines should be determined: for suspended pipelines, 0.005, and for underground pipelines, 18.
20.7. Installing revisions, cleaning, and observation wells in accordance with section requirements is necessary to maintain the network of internal drains. 17. If there are any indentations on the risers of the audit, they must be installed in the lower floors of the buildings and above them.
Note: It is permissible to forgo providing with the length of the suspended horizontal lines up to 24 meters at the start of the site.
20.8. Compensation bells with elastic sealing should be used to connect the drainage funnels to the risers.
20.9. The following formulas should be used to estimate the amount of rainwater q, l/s, that will be consumed from the water area:
For roofs with an inclusive slope of up to 1.5%
For roofs that slope more than 1.5 percent
Within equations (34) and (35):
F – Square Meters of Water;
Rain intensity, measured in liters per second (l/s) from one hectare (for a specific area), for 20 minutes, with a one-time period that surpasses the estimated intensity equivalent to a year (accepted in accordance with SNiP 2.04.03-85);
The formula determines the intensity of rain, expressed in liters per second (l/s) from one hectare (for a specific area), for five minutes, with a one-time period that surpasses the estimated intensity of one year.
The parameter used here, n, is based on SNiP 2.04.03-85.
20.10. The drainage riser’s estimated rainwater consumption shouldn’t go over the amounts listed in the table. 10, and on the drainage funnel is ascertained using the passport information of the chosen funnel type.
20.eleven. In addition, 30% of the total area of the vertical walls that rise above the roof and are adjacent to it should be considered when estimating the sequence area.
20.12. Distribution risers should be counted on to withstand hydrostatic pressure during clogs and overflow, as should all diving pipelines, including those buried beneath the first floor.
20.13. Cast iron, plastic, and asbestos-cement pipes should be used for internal gutters, keeping in mind the specifications of PP. 17.7, 17.9.
Steel pipes are permitted on horizontal suspension lines when there are vibration loads.
"Determining the right funnels is essential to maintaining efficient internal drainage systems. These parts are necessary to redirect rainfall and stop water damage in buildings. The main variables that affect funnel calculations are examined in this article, along with roof area, rainfall intensity, and drainage needs. Homeowners and builders can improve the effectiveness and lifespan of their roofing systems by making educated decisions by being aware of these computations."
Calculation of internal drains
Rainwater that has been lost or snowmelt that has fallen on the building’s roof melts and flows into the drainage funnels. Rainfall is the most common type of atmospheric precipitation, so internal drains should make sure that the maximum amount of rainwater that is expected in this area is removed.
Calculating the anticipated costs for rainwater
The following formulas are used to calculate the costs of rainwater, l/s, when calculating internal drains:
For flat roofs with less than a 1.5% slope
For roofs with pitched roofs and slopes greater than 1.5% –
Where: – the water column area, mg; – the rain intensity lasting 20 and 5 minutes, l/s from 1 ha (values are displayed in rice, 22.5); – the coefficient that accounts for the duration of the single exceeding the intensity and the roof’s capacity to accumulate rainwater, l/s from 1 ha:
= 1 in the 90 areas.
For areas 90, = 1.5
2 in relation to areas 150
The formula can be used to determine the value.
Where n denotes the degree indicator:
Between 0.75 and 0.75 in the country’s middle lane in the European section
0.5–0.7 in the southern regions;
In the nation’s Asian region, 0.65-0.7.
The table provides the intensity values. 22.1.
Rice. 22.5. Intensity distribution of rainfall
Calculating internal drains hydraulically
The hydraulic calculation is carried out with the building’s roof’s maximum amount of precipitation drainage.
The water movement regime in each individual element must be considered when calculating internal drains. All that remains of the computation is to ascertain the throughput of each individual element and the overall system of internal gutters.
From a hydraulics perspective, distribution funnels can be thought of as long nozzles that release liquid or as a ring spillway. In fact, a non-circular annular mode of water movement forms at the exhaust pipe of the drain at 3-5 of its diameter with a small layer of water on the roof. Depending on the funnel’s design, the consumption is determined by the height of the water layer H, the inner diameter of the funnel, and the coefficient of flow of M.
Since the drainage funnel is fastened to the riser, it will expand the water layer on the riser beginning at a length of (10+12). the water mixture forms a continuous pressure flow when the ring flow is closed, at
Which water consumption is already influenced by the riser’s height and hydraulic resistances.
An increase in the water layer in front of the funnel causes a vortex flow to form, which descends into the riser and carries atmospheric air with it. As they proceed down the riser, clicking occasionally, a mixture of water and air is created that eventually causes the air to leak. This kind of movement is identified by the existence of a vortex funnel, the creation of vibrations, and consequently a reduction in the riser’s bandwidth.
The pressure mode of water movement along the entire drain tract begins when the water layer on the roof near the drainage funnel increases to a certain critical level. At that point, the air suction stops and the vortex funnel vanishes. At the same time, rainwater consumption increases to its maximum value, and with an additional increase in the water layer above the receiving funnel, almost no increase in consumption occurs.
The riser and release components of the entire network operate in pressure mode once the water layer in front of the funnel reaches a critical depth.
The formula can be used to calculate the estimated critical consumption of rainwater, or l/s, which can bypass the funnel-state-output system.
Where m; Dear of the pipeline (riser and release); h is the pressure equal to the difference in the marks of the roof at the funnel and release; The following values correspond to the specific local resistance, (m ∙ s)/ at = 1, which depends on the conditional passage’s diameter, mm: I, hydraulic bias; – the total of the coefficients of local resistances of shaped parts, funnels, and release; – Water usage for living.
125150 200 250 75 80 100 125
∙.. 260 102 83 34 16.5 5.2 2.1
The formula can be used to determine the critical layer of water above the receiving funnel.
The formula is used to determine the critical rainwater consumption per funnel in liters per second.
Where is the estimated amount of atmospheric precipitation (critical pressure = 38, 49, 81, 115 mm for pipes with a diameter of 85, 100, 150, and 200 mm, respectively); G = 9.81 m/s is the free fall acceleration 2. The riser’s internal diameter in millimeters.
The riser’s diameter (85, 100, 150, or 200 mm) determines the maximum allowable flow rate of rainwater, which is 30% critical and can be taken on one of the riser’s drains (3.9, 9.6, or 19.5 l/s, respectively).
There are two ways to find out if internal drains are missing.
1. Calculate how much rainwater is anticipated to be consumed, as there is only one drainage funnel:
Where Q is the overall roof-wide rainwater flow rate: – the approximate quantity of funnels that will be installed.
The critical maximum consumption is compared to the consumption. which the computer can bypass.
If inequality is satisfied, then the system is appropriately designed.
If so, it becomes necessary to either decrease the water intake area per funnel or increase the diameters of the diving pipelines and risers, i.e., increase the number of funnels.
2. Calculate the anticipated cost of rainfall. Next, using the formula, the pressure loss that occurs when water moves under pressure along the gutters is determined.
If the pressure loss in the system is less than the system pressure (the difference between release and roofing), or H < H, then the system is correctly designed. The riser and diverts’ diameters should be increased if h is greater than h.
The materials placed on 185.154.22.117 © Studopedia.ru are not the work of the author. but offers the opportunity for unrestricted use. Is there a copyright violation? Write to us.
Maintaining the integrity and effectiveness of roofing systems requires an understanding of how internal drainage funnels are calculated. Rainwater is efficiently diverted away from the roof by well-designed funnels, avoiding water damage and preserving structural integrity.
A number of variables are taken into consideration when calculating funnels, such as the area of the roof, the anticipated intensity of the rainfall, and the necessary drainage capacity. The objective is to create funnel designs that can withstand the highest amount of rain that is predicted without overflowing or clogging, guaranteeing constant, efficient drainage.
The funnel outlet’s diameter is an important factor to take into account. The amount of water that can be released from the roof is directly impacted by this dimension. Greater water volumes can be accommodated by larger outlets, lowering the possibility of overflow during periods of intense rainfall.
Furthermore, funnel positioning is very important. Water is efficiently collected from all areas of the roof surface when they are placed strategically near corners or along the low points of the roof. The chance of standing water collecting on the roof, which over time may cause leaks or structural damage, is reduced by proper placement.
In conclusion, effective roof management requires a solid understanding of internal drainage funnel calculation. Roofers can make sure that rainwater is effectively and safely diverted away from the building by taking into account variables like funnel size, outlet diameter, and strategic placement. This will prolong the life of the roof and maintain the structural integrity of the building.
