Frequently asked questions - SL13 Backflow protection for drainage pipes
General
Who invented the Stop Silent SL13 backflow preventer?
Lasso Technik AG is a pioneer in backflow diaphragms for pressure media up to 16 bar. This expertise formed the basis for the development of a backflow diaphragm for media with solids content in the low pressure range.
The SL13 backflow flap was developed in 2013 by Mr. Daniel Rohrer and brought to market maturity in close cooperation with the Lucerne University of Applied Sciences and Arts in Switzerland.
The SL13 is manufactured, assembled, tested and marketed in Switzerland.
What distinguishes the Stop Silent SL13 backflow flap from its competitors?
Quick installation: the SL13 is installed in just a few minutes.
No structural adjustments required: no drilling, screws or dust. Autonomous and currentless
Also seals in oval pipes: e.g. DN150 an ovality of 20mm can be accommodated (140mm / 160mm)
Installation in inlet and outlet possible
Easy to clean: Easy to remove and reinstall for cleaning
Durable: The first backflow flap installed has been exposed to a backflow every 20 minutes for 2013 years and still works perfectly today."
How long does a Stop Silent SL13 backflow valve last?
Our membranes generally exceed a service life of 25 years in the water supply sector.
We have had in-depth knowledge of the wastewater sector since 2013. Our reference system at the sewer network operator of the city of Bern has been subject to a backflow every 20 minutes since 2013.
What materials is the Stop Silent SL13 backflow valve made of?
Membrane: EPDM rubber, is resistant to domestic waste water
Metal parts: Stainless steel 1.4404
Plastic parts: Polypropylene (PP)
Applications
Amphibian flap
Protects against the entry of insects, amphibians and small animals.
(Attention: the SL13 does not offer protection against rodents)
(Attention: the SL13 does not offer protection against rodents)
Protection against toxic gases
How does the SL13 backflow valve work?
The SL13 prevents backflow by means of a membrane combined with an expander clamp.
membrane is low-maintenance and durable, which makes it superior to mechanical dampers.
It remains closed in the home position and actively prevents backflow.
Even in the event of backwater, the membrane can open with a pressure difference of 2-3 cm on one side and allow water to flow out.
Backflow protection against water, protection against odors, gases, small animals (excl. rodents) and sound
Quick installation / retrofitting in new buildings, old buildings or renovations / installation possible from both sides (in the inlet and outlet)
How much slope does the Stop Silent SL13 backflow flap require?
A constant gradient is important to avoid deposits on the track.
Must be at least 2% constant gradient for wastewater pipes. If the gradient is less, please contact Lasso Technik AG.
For rainwater pipes approx. 1% gradient
Not suitable for vertical installation in waste water pipes, but as an odor trap in rainwater pipes above the backflow level.
Why does the diaphragm not drain completely?
The SL13 opens at a water level of 3/4 to 4/4 pipe filling on the inlet side and closes at approx. 1/2 filling.
The standing water also serves to prevent solids from settling and causing a blockage.
Backwater, what is it?
Backflow is the backing up of wastewater from the public sewer into the connected pipes. (An overload of the sewage network).
Risk of backwater
- Has there already been a traffic jam in your street?
- The hazard map provides information about your risk of backwater
- Do you ask the municipality about your backwater risk?
- The risk increases with additional buildings on the same sewer line.
The backflow level is where the water emerges from the sewer system. This is the maximum water column that presses over the house connection towards the cellar.
The backwater calculator shows how quickly how much water can get into the cellar. The water pushing back can reach 60 liters or more per second
What must be protected by the Stop Silent SL13 backflow flap?
- Basement rooms or underground garages that can be flooded.
- The installations, furniture and electrical installations as well as the lives of people and animals.
Assembly situation
The SL13 can also be easily retrofitted in existing homes — without any structural modifications.
It can be installed to protect against sand and debris being washed into a pipe end or to prevent small animals and insects from entering.
Installation in inspection / control shafts
Installation in a plaster opening
Into an accessible pipe, whereby a piece of at least the length of the SL13 is cut out. The SL13 can be installed in this piece of pipe. The whole thing is then reassembled with 2 pipe couplings.
Installation
- Clean the entire situation and remove incrustations
- Measuring
- What mounting aids are available?
- It is important to consult the checklist before purchase and installation.
- We recommend using a cardboard wedge to measure the inside diameter of the pipe.
- You can find the installation video here
- A photo of the pipe clarifies the situation and shows incrustations, pipe reductions and pipe bends, which must be taken into account before installation.
- In which pipes can SL13 be installed?
- Basically in all types of material such as plastic, concrete, ceramic or steel.
- The inside diameter of the pipe must correspond to the clamping range of the SL13. Adapters can be manufactured outside this range. For example, we manufacture an adapter for the SL13 DN125 for an internal pipe diameter of 140 mm.
- Plastic pipes are often deformed, so measure horizontally and vertically
- A photo in the pipe clarifies many things, reduction, pipe bends, incrustations...
- Measure the inside diameter of the pipe with a cardboard wedge, see...
- The gradient for domestic wastewater is greater than 2% according to the standard and therefore sufficient for the SL13. However, if there is any uncertainty, this should be checked. This depends on the accessibility and should be carried out by an expert company with a sewer camera or a surveying device. If this is not possible, the inspection interval after reinstallation should be kept short.
- Slide in SL13 and clamp. (mounted in a few minutes)
- Function check, observe opening and closing of the diaphragm.
Can the Stop Silent SL13 backflow flap be installed in both the inlet and outlet of an inspection chamber?
Yes, the Stop Silent SL13 backflow flap can be installed in both the inlet and outlet.
A lot of rainwater:
The decisive factor is the amount of rainwater that can flow into the shaft during an incident. If a lot of rainwater is expected, the SL13 should be installed in the inlet from the basement.
A lot of rainwater:
The decisive factor is the amount of rainwater that can flow into the shaft during an incident. If a lot of rainwater is expected, the SL13 should be installed in the inlet from the basement.
Little or no rainwater:
If little or no inflow of rainwater is to be expected, SL13 can be braced in the outlet of the inspection chamber. In this situation, the inspection chamber and the pipes serve as a reservoir for water during a backflow.
If little or no inflow of rainwater is to be expected, SL13 can be braced in the outlet of the inspection chamber. In this situation, the inspection chamber and the pipes serve as a reservoir for water during a backflow.
Maintenance
Should be done at least twice a year
Clean the situation, do not use high pressure or cleaning spirals
Function check by observing the opening and closing of the diaphragm
In the event of malfunctions: Dismantling, cleaning and checking for damage
Costs
The costs are low compared to the damage caused by backwater in the basement.
The cost of backflow prevention depends on the pipe dimensions.
The overall project costs are relatively low, and no or hardly any structural modifications are necessary. There is no need to lay power lines.
The pure installation costs are negligible.
Maintenance does not require specialist training. A visual function check is necessary and can be carried out by the homeowner.
Some insurance companies contribute financially to the installation of backflow protection, as this brings them more benefits than costs in the long term. For further information, please contact Lasso Technik AG."