There are two primary methods for conducting a drain test: the air test and the water test. Additional techniques include smoke testing and mandrel testing. These tests are crucial to ensure that newly installed plumbing systems are leak-free and meet industry standards. Each segment of a plumbing or underground pipe system plays a critical role in maintaining the integrity of the entire system. Performing multiple drain tests helps identify potential leaks in a recently installed system. Proper drain testing is essential to ensure compliance with UK regulations.
Typically, you'll conduct a drain test before an official inspection and repeat the process in the presence of a building control officer.
Key Takeaways:
- The most common and reliable methods for drain testing are air testing and water testing.
- A Building Control Officer's approval is necessary for your drain test to be valid.
- For drainage systems shorter than five meters, if there’s visible damage, it usually indicates excessive water loss.
Things to Consider Before Conducting Drain Tests (Drain Testing Procedure and Building Control)
Before proceeding with a drain test, examine all pipelines for existing damage or leaks. If you’re dealing with jointed systems, allow them to fully drain for at least two days before starting any tests to ensure any issues are clarified.
Furthermore, before beginning the drain test, a building control officer must be present. However, it’s advisable to confirm that the drainage system is functioning properly beforehand by running the system prior to the officer’s observation.
What is Smoke Testing?
Technically, smoke testing isn't considered a definitive assessment of a drainage system's water tightness. However, it’s a useful tool, especially with uPVC piping, to detect leaks and other faults that might not appear during air or water tests. Always consult manufacturers before conducting this test, as it could potentially damage certain types of pipes.
What is Mandrel Testing?
Mandrel testing is used to evaluate the quality of an installation. It involves inserting a small object, called a mandrel, into the pipe to check the uniformity of the pipe's diameter. Mandrels typically have a slightly smaller diameter than the pipe itself—for instance, a 150mm pipe would use a 135mm mandrel. Mandrels are cylindrical objects that help ensure the pipe meets specifications.
How Does a Drainage Air Test Work?
An air test is a quick and effective way to verify that individual pipes and drain runs are functioning correctly. This is done by isolating a specific section of the drain with two gauges set at pressures of 110mm head for five minutes, providing pressure readings. Afterward, the head is adjusted to 100mm for another five minutes. Any significant changes in pressure are measured. This method provides an accurate way to detect issues but cannot be used on all types of drains and systems. For instance, a decrease in temperature by just 1 degree inside the pipe can cause the test to fail.
Drain Testing Procedure for an Air Test
Begin by fitting a bung at the head of the pipe run with the appropriate nipple cap to connect it to the hose that will be attached to the manometer. Ensure your manometer is partially filled with water beforehand.
Next, use a hand pump to increase the pressure until the manometer reads between 125-150mm. After this step, allow the equipment to sit for 10 minutes to stabilize before reducing the manometer's pressure to 100mm.
Monitor the manometer for five minutes; it must not drop below 75mm. This indicates a pass, but if it does fall below the 75mm mark, inspect for leaks and other signs of failure. Rectify any issues before conducting another test, and if it still fails, proceed to a water test.
How Does the Drainage Water Test Work?
Water testing, also known as water drop testing, is a method requiring less pressure but takes up to 2 hours to set up. The test works by blocking both ends of the system, charging it with water, and monitoring the water levels either at a manhole or access point. No additional pressure should be applied during the water test. The water level should be limited to 1.5 meters from the lowest invert level of the drain being tested. This method allows for testing an entire system at once, which benefits everyone involved in the process.
Drain Testing Procedure for a Water Test
Two sets of test parameters must be followed, depending on the pipe size. For pipes ranging from 100-400mm, follow BS8301 rules: a 1500mm head at the high end and a maximum head of 400mm at the low end. For pipes between 400-750mm, follow BS8005 rules: a 1200mm head at the high end and a maximum head of 6000mm at the low end.
First, block the lower end and all open branches, then add a 90-degree bend to the top part of the run along with a vertical pipe of the same diameter. Secure the vertical pipe to a fixed object like a wooden post.
Add water to the required head level in the vertical pipe based on the rules you're following (BS8301 or BS8005). Allow the water to stand for two hours, then top it up to the essential level specified in the guidelines for your pipe size.
Monitor the process for half an hour, ensuring the water head remains filled as needed, while recording the amount of water added. After the half-hour mark, calculate the maximum permissible loss by determining the amount of water added. For example, the loss should not exceed 1 liter per hour per meter of pipeline per meter of inside pipe diameter.
Making Repairs
It’s not uncommon to need repairs after running a drainage test. Often, it’s a matter of replacing a faulty length of pipe or redoing a joint. However, if there’s no obvious fault, it might require disassembling the entire system and testing each section individually using an air test. After identifying the issue, rerun the tests to ensure everything functions correctly. You may need to replace a section of pipe or rejoin and reseal parts of the system.
When it comes to manhole covers and inspection chambers, it’s common for joints to leak, but this is usually an easy fix through rejoining and resealing. However, if the problem lies with the base and concrete sealing of the pipe, epoxy mortar may not suffice. In such cases, the only solution is to completely rebuild, which isn’t ideal but necessary according to regulations. As always, retest after attempting to fix any issues within the system.
How to Water Test a Manhole and Inspection Chamber
The process is similar to a regular water test. First, bung up all open-ended outlets, then fill the manhole chamber with 300mm of water.
Afterward, wait a minimum of one hour and no more than two hours, then visually monitor the water inside the chamber for half an hour. In most cases, a water loss of below 25mm over 10 minutes is considered a pass, but if uncertain, use the same calculation as with the pipes to determine this.
What Are Classed as Acceptable Leakage Rates for the Drainage Water Test? (Litres in 10 Minutes)
110mm Diameter Pipe: 0.2l per 5-10m, 0.4l per 10-20m, 0.6l per 20-30m
160mm Diameter Pipe: 0.3l per 5-10m, 0.6l per 10-20m, 0.9l per 20-30m
200mm Diameter Pipe: 0.4l per 5-10m, 0.8l per 10-20m, 1.3l per 20-30m
225mm Diameter Pipe: 0.5l per 5-10m, 0.9l per 10-20m, 1.4l per 20-30m
What Happens with Drains Less Than Five Meters Long?
If your drainage system is less than five meters long, use common sense to assess whether the leakage is acceptable. A general guideline is that if there’s visible damage, it’s likely more water is being lost than expected. Generally, an amount less than 25mm in ten minutes is not considered a concern.
What’s in a Drain Testing Kit?
At EasyMerchant, we offer both an air testing kit and a drain testing kit suitable for your job requirements. The drain testing kit includes the essentials needed to test a drainage setup:
- Air tubing
- ‘U’ air gauge (manometer)
- Y-piece
- 4″ plugs/bungs and a ½†brass nipple
- Hand bellow
Drain Testing Bags
Drain testing bags are versatile tools used across industries like sewage, petrochemicals, food processing, and mining. Their adaptability makes them ideal for testing in confined spaces. Smaller sizes often come equipped with Schrader valves or brass air traps, while larger ones feature ball valves for inflating with a compressor. They can also be fitted with pressure gauges to prevent overinflation.
Drain Testing Bungs
To correctly test any pipework using either the air test or water test, expanding bungs are essential and among the most important pieces of equipment. These bungs have a metal outer shell that pushes the rubber inner core outward (to block off the pipe), a hollow mid-section with a nut that adjusts the compression of the device. If you can't connect the bung to a manometer, fit a nipple to the end, and if that doesn’t work, an end cap creates a secure seal.
Bung sizes vary depending on the pipe size required for the job. For a 110mm drainage pipe, you’d need a 100mm (4-inch) bung. For a 225mm pipe, a 150mm (6-inch) bung would be required. At least two bungs will be needed depending on the property and pipeline being tested—one for each end.
Ensure there are no issues or dirt that could interfere with the installation and function of the bung before attempting to fit it, as any grit or dirt within the seal could cause leaks and result in a failed test.
When applying the rubber bung, open it out to make the rubber section’s diameter smaller before inserting it into the pipe. Tighten it afterward to expand it again, creating a strong seal that presses against the inner pipe wall, ensuring the pressure gauges provide an accurate reading.
At EasyMerchant, we stock the necessary equipment for conducting a drain test and have extensive knowledge of the process. Feel free to reach out if you have any questions.
Shop Drain Testing:
Drain Testing Bungs
Drain Testing Kit
The Basin Waste and Bottle Trap as one part of faucet accessories, for offering great user experiences, we provide suitable basin wastes and bottle traps for the faucets.
Yunspire has 20 years exprience in manufacturing Faucets & Bathroom Accessories in Guangdong, China.
Our manufacturing process advanced technology with superior materials, rigorous testing, and comprehensive quality control, all to ensure your complete and total satisfaction. If you have any questions, please contact with us directly.
Sink Tap Accessories,Kitchen Tap Accessories,Brass Faucet Accessories
WPWF (JIANGMEN) Sanitary Ware Company Co.，Ltd. , https://www.yunspirefaucet.com