If you’re searching for the ideal Precast Concrete Sand Trap Supplier, you’ve come to the right website!
The only thing a sand trap is supposed to do is capture sand, grit, and coarse sediment before it gets to the downstream drainage network, and continue to do its job in every storm and desert wind event—without clogging the pipes that it’s supposed to protect.
When it works, people don’t think about it.
If it doesn’t, then the problem is most likely the supplier responsible for designing and casting the trap.
This guide takes you step-by-step through the process of evaluating a precast concrete sand trap supplier to keep your drainage system flowing, and not blocked.
How the Manufacturer Does the Job Is Much More Important Than What They Actually Are Doing
The initial considerations most buyers come up with are the chamber size, diameter of inlet and outlet pipes, and price per unit.
While this is a good beginning, it doesn’t cover the equally important aspect of how the supplier sizing the sediment storage volume, details the flow path inside the chamber, and plans for the trap to be desilted without the need to shut down the drainage line above it.
The stresses in sand traps in the UAE are a specific combination; the fine desert sand being blown in by wind, coarse grain being washed in during storms, and long dry periods between storms in which the sediment is simply sitting and hardening.
A supplier who considers the sand traps as a structure for sediment management, that is, one around settling velocity and access to sediment management will plan for that from the outset.
If a person uses it as a general chamber with inlet and outlet pipe, he or she will give a unit which will fill up with compacted sand within a year, and failure to protect anything downstream.
Be Sure to Order What You Really Need
It’s essential to understand what kind of sand trap your project requires before comparing sand suppliers since not all precast manufacturers provide this capability.
Inline Sand Traps
The most common type seen in road drainage or car park runoff, Inline Sand Traps are located right in the way of the flow and are made up of a drop chamber or sump below the pipe invert where sediment can be allowed to settle from the flow before it goes downstream.
Chamber-Type Sand Traps
Chamber-Type Sand Traps are larger, standalone traps that are usually located in front of a pump station, attenuation tank, or soakaway where there is a larger volume of sediment stored in the trap to protect equipment further downstream.
Combined Sand and Oil Separators
Combined Sand and Oil Separators are used at fuel stations, workshops and vehicle wash sites where runoff contains both sediment and oil, and combine settling the sediment with a hydrocarbon separation stage.
Road Gully Sand Traps
Road Gully Sand Traps are smaller traps installed within road gully pots to trap sediment before it even gets to the main gully.
If you know which of these — or which combination — your project requires, you can narrow down and find those suppliers that design specifically for sediment control instead of an ordinary precast manufacturer that provides a modified manhole as a sand trap.
Learn How to Size Sediment Storage Tanks
If a sand trap is too small for the catchment area then it fills up quickly and loses its effectiveness much sooner than the next clean out.
Inquire from the supplier how they determine the appropriate size of sediment storage; do they size it based on your catchment site characteristics, surface type and sediment load, or do they use a standard range of sizes based on a specific site type that may or may not be suitable for your catchment?
If you ask a supplier what size he recommends and what he expects your catchment area, he is designing for your project, if he quotes a size off a catalog, he is just guessing.
Examine How They Handle Flow Path and Settling Design
It is the inside shape of a sand trap that causes sediment to drop out rather than pass through to the outlet pipe.
Question the position of the inlet and outlet relative to each other, if there is a baffle or drop to reduce the flow velocity in the chamber and how deep the sump is below the outlet invert.
If the outlet is too close to the inlet or if the sump is too shallow, the high velocity of the water stream carries sediment through the settling area without it ever stopping — and the structure is no longer effective.
Make Sure to Check Their Manufacturing Quality Control
On paper there is no difference between two traps and yet, they may perform differently when they are actually constructed.
Inquire about how the sump and invert are formed, the curing process used and what inspection is completed prior to unit shipping.
A poor formed invert will show up later as a poor settling flow or wear of the inlet early in the life of the flow path.
Request Drawings That Are Engineered and Flow Calculations
A good supplier would be able to draw up drawings for your project, not a cut sheet.
For sand traps it is confirmed inlet pipe and outlet pipe sizes and invert levels, a structural load rating based on what is over the top of the chamber, road, car park or landscape area, and sediment storage volume based on the catchment area.
If a supplier cannot provide calculations that are specific to your site, catchment and expected sediment load, then you are likely to purchase a generic chamber that is designed for a different catchment and sediment load.
Desilting and Maintenance Access – Compare
To keep a sand trap in operation, there has to be someone willing to remove sand.
Inquire about the access the supplier’s design offers for desilting: a removable cover that fits a vacuum tanker hose, adequate headroom for maintenance equipment, and a chamber shape that doesn’t provide dead corners where sediment can get compacted and is difficult to access.
Any trap that appears effective on the paper but is cumbersome to desilt gets ignored in a year or two, and is a failure.
Research and Verify Their Reputation and History
Sizing calculations and designing the flow-path tell you what a supplier will do.
Installed projects provide you with information about what they actually brought.
Request some examples of sand traps provided for sites that share a similar catchment size and surface type, and ask for photos or maintenance records taken well after the traps were erected, not at the time they were delivered.
If a trap has been settling sediment well and is being desilted on schedule in a few years, it is a testament to the design of the supplier, not any brochure.
There Are a Number of Red Flags to Watch Out For
Some indicators can accompany each other if the supplier is not a sediment control specialist:
- When they don’t have a clear answer on sizing of a sediment storage.
- They don’t appear to be willing to provide a catchment-specific calculation.
- They don’t explain desilting access.
- They offer a price that seems to be significantly lower than the rest of the market without providing an explanation.
None of these are necessarily disqualifying, but two or three should be given particular attention.
Integrating All Aspects of the Project
The answer lies in knowing what type of precast concrete sand trap you need on your site, knowing that the supplier sizes the trap according to your actual catchment area, and knowing that he or she designs the flow path to the trap to settle your sediment and is able to design the trap with practical access for desilting, and that the manufacturer has quality control in place to assure actual production quality, and that the supplier is able to provide a track record of traps that actually work after installation (not just on a drawing).
If it is done correctly, the trap will serve its purpose perfectly: it will catch the sand before it has a chance of becoming a drainage network problem.
