How to do a BRE 365 Percolation Test: A Simple Guide

How to do a BRE 365 Percolation Test: A Simple Guide

When planning any development or drainage system installation, a BRE 365 percolation test is essential to determine the soil’s percolation rate. This test ensures that water can be properly absorbed into the ground, preventing flooding or pooling issues. If you’re unsure about how to conduct the test yourself, IBEX Consultants offer expert services to guide you through the process and ensure accurate results. In this article, we’ll explain how to perform a BRE 365 percolation test, step-by-step, with tips to ensure accuracy and compliance with local authority regulations.

What is a BRE 365 Percolation Test?

Percolation tests are used to determine how quickly water drains through the soil. The test is required by planning authorities to ensure proposed drainage systems (soakaways) are suitable for the site’s soil. If the percolation rate is too slow or too fast the drainage system won’t work and will flood or not absorb enough water.

Tools and Equipment

  • Tape measure
  • Trial pit (hole that will be filled with water)
  • Water supply (enough to fill the pit multiple times)
  • Measuring device to check the water level
  • Excavation tools to dig the hole
  • Timing device for accurate measurements

Step 1: Where to Place the Hole

The test hole should be placed in the area where the drainage system or soakaway will be installed. Make sure it’s within the site boundary and in the area with the best soil. Avoid areas with a high water table as this will affect the results of the percolation test.

Step 2: Dig the Hole

The hole should be dug to the same depth as the proposed soakaway or drainage system (usually 1-2 meters deep) and 300mm wide. The pit should be deep enough to reach the soil that will affect the water absorption rate. For example clay soils have poor percolation and sandy soils drain faster.

Step 3: Fill with Water

Once the hole is ready fill it with water to soak the ground. This simulates a heavy rainfall when the soil is saturated. Fill the pit to about 75% of its capacity and let it drain. You need to allow the ground to become saturated before you start measuring the percolation rate. This may mean refilling the test hole several times depending on the soil’s absorption rate.

Step 4: Measure the Percolation Rate

Once the water has drained fill the hole again to a known depth (usually 75% of the full depth) and measure how long it takes for the water level to drop by a specified amount (usually 10mm). Use a tape measure to record the drop in water level over time. Repeat this process at least three times to get an average percolation rate. The slower the water drains the less permeable the soil is which will affect the proposed drainage system.

Step 5: Record and Submit

Once you have finished the testing record the results in detail including the water level readings, depth of the test hole and percolation rate for each test. This will be required for your planning application to the local authority.

Common Problems with Percolation Tests

  1. High Water Table: If the water table is too high it will affect the results by not allowing the water to soak into the ground.
  2. Clay Soils: Clay soils have very slow drainage rates and are not suitable for soakaways without significant ground alteration.
  3. Incorrect Test Pit Depth: If the pit is not deep enough it will not reflect the actual performance of the drainage system once installed.

Costs and Time for BRE 365 Percolation Testing

The cost of BRE 365 testing will vary depending on the site location, soil type and size of the area to be tested. Testing can take a few hours to a couple of days depending on the soil type and conditions. Hiring a professional team to do the testing ensures accuracy and compliance with local authority regulations.

Why BRE 365 Testing is Important

Percolation testing is crucial for any drainage system to be installed. It will help you determine if the soil can handle water runoff and if modifications are needed. This will prevent potential problems like flooding or water discharge that can damage the environment or nearby buildings.

Conclusion

Now that you know how to conduct a BRE 365 percolation test, you can ensure your site meets the necessary permeability and water management standards. Following the correct steps will help you avoid costly issues down the line. If you need professional assistance, consider contacting IBEX Consultants. Their team of experts can perform percolation testing and provide guidance tailored to your specific site and development needs.

For more information or to schedule a percolation test, get in touch with IBEX Consultants, who offer bespoke services to ensure your project complies with all local regulations and achieves optimal drainage performance.

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