[Drainage Counterflow Battle] Heavy rain caused the toilet and floor drain on the first floor to spray feces? Detailed explanation of the modification method of "anti-backflow one-way check valve" and "sewage diversion pipe" in Greater Taipei

Backflow Nightmare: Physical Backflow Pressure Caused by Overloaded Rainwater Sewers

In low-lying and riverside communities in the Greater Taipei Basin (such as Sanchong, Wugu, Wanhua, Datong), many first-floor residences and basements of old apartments Commercial offices or prime street stores often face a very destructive pain point: whenever a typhoon or a disastrous afternoon thunderstorm strikes, the toilet, bathroom floor drain, and kitchen sink in the house will suddenly spew out foul-smelling black cement, sand, and even feces like a fountain. This is because during heavy rains, the city's public rainwater sewers and the sewage sewers outside the building cannot drain well enough, and the water level in the main pipes rises sharply, creating a huge "backpressure." This high pressure will flow back through the building's public drainage risers to the weakest low floors (usually the first floor or basement), causing severe asset contamination and furniture damage, directly destroying the operational value of the commercial space.

A fundamental protection tool: Install a one-way check valve (Backwater Check Valve)

To prevent the reverse flow of external sewage, the most effective physical defense line in hydropower projects is to install a "check valve (Check Valve)" at the outlet of the building's drainage main pipe or on the indoor first-floor drainage trunk line. There is a flap inside the check valve that can be opened in one direction. When the wastewater in the house is discharged outward, the water flow will push open the baffle and flow out smoothly; when the external sewer water flows in the reverse direction, the reverse pressure will tightly press the baffle against the outsole rubber air-tight gasket, locking the channel and blocking the return flow of waste water. Water and electricity experts remind that check valves must be made of white iron or thick-walled PVC with a "maintenance and cleaning port" so that hair and debris stuck in the valve can be cleaned regularly to prevent the valve from becoming stuck and failing.

Advanced waterway renovation: independent drainage and sewage diversion pipe modification method on the first floor

Another design flaw in large old apartments is that the first floor and the second to fifth floors share the same drainage pipe. Even if there is no backflow of external sewers, if residents above the second floor consume a lot of water and the lower end of the main pipe is clogged, the sewage discharged from upstairs will spray directly from the floor drain on the first floor. The most radical modification method is to carry out "modification of independent pipelines on the first floor (sewage diversion)". The plumber will knock open the floor, cut off the drainage pipes of the bathroom and kitchen on the first floor from the common pipe of the building, and connect a new pipe to drain directly to the ditch outside the building. Although this concrete work and water and electricity pipe improvement project requires knocking out part of the floor, for prime storefronts or commercial properties that are intended to be held for a long time, eliminating the hidden dangers of flooding and spraying feces once and for all is a gold CapEx investment that improves the liquidity of the asset market and avoids tenant claims.

Commercial store Flip pit prevention: preventive underground drainage health inspection

For real estate investors who specialize in acquiring, renovating, reselling or leasing old stores in the Shuangbei area of ​​Taipei, the integrity of the drainage system of the first-floor store is a hidden key to profit. If the store discovers after signing the contract that heavy rain will cause drainage and backflow, the repair costs and decoration damage will directly eat up the investment profit. During the acquisition evaluation stage, dispatching a water and electricity team to use borescopes to check the direction of sewer lines to confirm whether check valves have been installed, or to evaluate the space and budget for independent pipe modifications on the first floor, can ensure a leading position in business negotiations and is an indispensable risk control method for high-end real estate investors.

The Ministry of Economic Affairs' latest "Regulations on Consumer Electrical Equipment Installation" and the key points of electricity safety in old houses

Due to the popularity of high-power household appliances (such as air fryers, microwave ovens, dishwashers, instantaneous electric water heaters, and IH furnaces) in recent years, the Energy Administration of the Ministry of Economic Affairs has revised the "Regulations on Consumer Electrical Equipment Installation" many times to strictly require the diversion and protection mechanisms of residential electricity circuits. Statistics show that more than 30% of building fires in Taiwan are caused by electrical factors, among which "old wire insulation deteriorates and short circuits", "socket contacts are oxidized and loose, poor contact" and "non-fuse switch (NFB) overloaded and failed to trip" are the three main fatal causes.

Old apartments in Shuangbei that are more than 30 years old have a total original designed power capacity of only 30A to 40A, and several rooms often share the same 1.6mm or 2.0mm circuit. In the modern standard safety configuration, kitchen electrical cabinets, bathroom equipment, and air-conditioning and heating machines must all be equipped with 5.5mm² dedicated circuits (single circuit and single socket). It is recommended that the main switch box be upgraded to a busbar (Busbar) integrated distribution board, and the total amperage is increased to 75A or 100A (a qualified electrical appliance contractor needs to be entrusted to Taipower to review the additional power capacity).

Residential electricity self-test and regular inspection checklist

• Appearance and temperature of the socket: Touch the outer cover of the commonly used socket lightly with the back of your hand. If it feels lukewarm or if you find that the plastic socket is yellowed and charred, or the plug is loose and shaking after being plugged in, it means that the internal copper plate clamping force is exhausted or the contact resistance is too high, and you should immediately cut off the power and replace it.
• Regular testing of leakage circuit breakers (ELCB): For leakage circuit breakers in humid places such as balconies, bathrooms, and kitchen sinks, regulations require that the "TEST button" on the switch be pressed once every 1 to 3 months to confirm that it can automatically trip and cut off the power supply instantly.
• Serial connection and overloading of extension cords are strictly prohibited: Extension cords should be purchased with 2.0mm thick wire diameter products that have CNS certification and automatic overload power-off protection. Do not share the same extension cord with high energy-consuming appliances to ensure zero hidden danger to life and property at home.