A standard kitchen sink waste trap is typically 40mm (1 ½ inch), connecting to the sink's waste outlet, while the pipe connecting to the wall/floor is usually 40mm or 50mm, often adjustable to fit either. Larger kitchen sinks, especially with garbage disposals, might use larger connections, but 40mm is the common standard for basic setups, with 50mm for double bowls or increased flow, according to Angi.
Wash hand basin (bathroom sink) wastes use a 32mm / 1-1/4 inch trap. Kitchen sinks and baths use a 40mm / 1-1/2 inch trap.
Kitchen sink P-Traps come in 1-1/2” standard size, while bathroom sinks use P-Traps of 1-1/4” standard size. The traps also come in different material types such as propylene, ABS, brass (chrome-plated or natural), and PVC.
the simple answer is that basin wastes are 1¼” BSP (32mm), whereas bath and kitchen sink wastes are 1½” BSP (40mm).
Most bathroom sinks have a 1 ¼-inch drainpipe that connects easily to a 1 ¼-inch P-trap. Sometimes, certain bathroom sinks may have a slightly larger pipe.
As mentioned, kitchen sinks use a 1 1/2 inch pipe, while bathrooms often utilize 1 1/4 inch pipes. This difference helps in managing the flow of water, preventing backups that can occur in smaller pipes.
40mm waste system is the common size for bath and kitchen sink installation.
Using the wrong diameter trap affects drainage performance. 32 mm – for basins and small bathroom sinks. 40 mm – for kitchen sinks or baths. 50 mm – for utility and high-flow applications.
A 32mm waste pipe is typically used for appliances that present low volumes of water to the system (e.g. small hand basins), while 40mm is normally used for kitchen sinks, showers and baths. 50mm, on the other hand, is large to suit commercial applications or connect multiple waste pipes to a single flowing system.
How to measure basin waste size
Replace the sink trap to deal with buildup and clogged pipes that a plumber's snake or plunger can't fix. Replacing a sink trap is pretty quick work. You'll need groove-joint pliers, a bucket, and a replacement sink trap. (Take the old trap with you to the store to get an exact match.)
Measure the Diameter: Use a measuring tape or ruler to determine the diameter of the drain mesh or the underside of your existing sink plug.
Traps come in 1-1/4 inch (standard bathroom sink) or 1-1/2 inch (standard kitchen sink) inside diameter sizes. Be sure to check so you get the right size replacement at your local store.
32mm nominal internal bore (outside diameter is bigger at approx 34.5mm) plastic waste pipe x 1 foot, available in white, black or grey. This size is popular for bathroom basin wastes.
3/8 Inch Supply Line
Common Use: Often used for bathroom sink water lines or kitchen sink water lines with a moderate flow rate.
All basin wastes are the same size at 11/4" or 32mm. All bath /sink wastes are 1½" or 40mm BSP (British Standard Pipe).
Waste pipe sizes
40mm: Normally used for kitchen sinks, showers and baths. 50mm: A large pipe commonly suited to commercial applications or connecting multiple waste pipes to a single flowing system.
1" pipe actually has an outside diameter of 33.4mm. 1" pipes or spigot fittings (measuring 33.4mm outer diameter) will slot inside one end of this socket to be solvent welded, and 32mm pipes or spigot fittings will slot inside the other end.
Pipe Size. According to foundation repair experts, a typical French drain system in a residential home has a four-inch diameter. But if the area experiences a high volume of water, it might be suitable to install six or eight-inch pipes.
Because P-traps are vented and maintain a consistent water seal, they're more reliable in the long run. S-traps can dry out more easily, especially in fixtures that aren't used often, creating health and odor issues. P-traps require less frequent maintenance to remain effective.
A specialized fitting called a p-trap creates a powerful barrier that stops sewer gas and odor from entering your home. The trap is employed in any plumbing system that uses a drain and accepts sanitary waste from tubs, showers and sinks.
40 mm (1.1/2") BS EN 1451-1 plastic pipe. Do not solvent weld. The actual pipe size is approximately 41 mm o.d. x 36 mm i.d..
Why Does Waste Pipe Come With Different Sizes – 32mm and 36mm – 40mm and 43mm? Understanding the Basics. Discover the two primary types of waste pipes: push-fit and solvent weld. Each variant boasts distinctive characteristics and applications, providing diverse solutions for various plumbing needs.
Will join 40mm to 43mm and anything in between.