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Do you need to install concrete rings for your pipe inspection or for some other reason? Or maybe would you like to learn more about the installation process?
Installing concrete rings is achievable in four steps, a process explained thoroughly in the following article.
Before you begin your manhole installation
For a start point, you and your team should understand the needs of manhole installation requirements.
We suggest you insure that any equipment on-site be regulated by both Use of Work Equipment Regulations 1998 (PUWER) and Lifting Operations and Lifting Equipment Regulations 1998 ensuring your employee’s safety and avoiding legal trouble.
Machines and Manholes
To excavate your manhole destination`s you’re going to need multiple appliances. These machines include:
- Excavators (with set aside a backhoe for wider digging).
- A 360-degree slew machine, also for larger manholes.
- Big bucket for digging, with chain and sling mounts.
For transporting your equipment, the obvious but outsourceable:
- Lorry for moving your equipment.
- Crane for loading and offloading materials or equipment.
To remove more room for a concrete manhole chamber a 360-degree slew machine may be required to complete this work. For the digging itself, you really can’t take the easy route.
Home-made or even in situ buckets are not suggested as the mortality rate doesn’t damage your pocket, it would damage the quality of your work.
Please enquire about a chain and sling mountable bucket with approved lifting points integrated. Moving your machinery and equipment about is another part of the process you need to ensure follows the rules.
Prioritize your chambers, rings, etc., arrive standing up. You don’t want anything coming off the lorry.
Use appropriate transport for the devices you will be moving about your site. When you are moving your manholes, please make sure that each chain or each cable is the required length to safely move each object and avoid contact with the tongue and groove areas.
From your suppliers, you’ll need to have lifting bolts in. These bolts fill the gaps in the three 50mm round holes punched on your equipment. Even the slabs covering the chambers have three points for lifting.
All lifting points need to be used to ensure that no breakage or damage to your manhole parts.
Construction of manholes
Next, we’re on to construction. The complete how-to build concrete inspection chamber and all that comes with it.
Your manholes base itself usually gets developed on-site to save cash outsourcing things like concrete septic rings and concrete septic tanks. They are usually lowered to at most, 2 inch (50mm) over your next pipe on the same height.
Lowering the ring onto the concrete you can then place the ring in again at most 3 inches (75mm).
Next up are our homemade base slabs. Always set on top of 2 layers of bitumen sealant or 2/5 inch (10mm) thick sand or mortar bed, 3:1 with all inlets and outlets benching being inducted afterward.
When achieved we can move on to building our manholes to the correct height. Our joints are made with a sealant or like mentioned before, sand or cement mortar you can learn about these from the link.
Your cover slab is then set on a layer of sealant. If larger then you can check use two layers.
You may need other surroundings for your concrete manhole chambers, shutters are there for you to use if needed.
Finishing off the process your ground-level manhole piece can be done using your B-class engineering bricks or your pre-casted adjusting concrete units with your covers and your frames completed on level ground.
More materials used, more to the side of bedding for your man-holes are compressed to fit the ideal radius of any cement cover. Your engineer can play a huge part in figuring out what’s needed based on the conditions of the earth below or the thickness of the bedding.
Pipe connections
For pipe connections, we should advise that you use your manufacturer’s recommendations, check with them to see which pieces are needed.
Flexible Boot Connections
Ensure the tidiness of the inner and outer walls of your pipes, place the pipes fittingly inside the whole wall or however else instructed.
Keeping the center of the connector in place you can install any clamps in any grooves shown and if required at the receiving end of your connector you can tighten the grips to the needed amount.
This will all depend on your part’s suitability. Again, check with your manufacturer.
To align properly, make sure everything is straight and level before adding your clamps to your part, this will leave time for your grouting or any O-Rings or sealants needed for this work.
Any sealant or protective equipment should be inspected to ensure no blockage and smooth connection between anything. Blocking up or hindering this should be avoided.
Compression Type Connector
For a compression-type connector, you must be sure to cut ¾ of an inch bevel on the end of your pipe. This leaves room for easy installation and proper fitting.
Cleaning both pipes and connectors on the inside and out makes for more professional work, causing less hassle in the future.
You can lubricate the surfaces and insides areas of any connector, fitting the beveled end you crafted before easily at the same level. Keep your pipes level is important due to the need to follow specifications.
Mortar Joint
Firstly, make sure that your openings are at the right heights. Then using non-stick mortar you must fill any gaps around your pipes to ensure no gaps.
You must be certain your mortar is dry before filling the surrounding earth to bury your work.
On our ongoing venture of learning the ins and outs of our concrete manhole set-up, we will be looking into the correct ways of backfilling.
Backfilling, or put simply, filling the space between your man-hole and the ground surrounding it you must start by removing any large rocks or anything that will prevent your packing machine.
Fill from the ground up with said material and pack using a vibration compression machine to densely surround your manholes holding them in place for further work.
Doing this leaves little room for damage to punch through and strengthens your man-holes by evenly distributing any weight.
How to test your man-holes performance
As a procedure you can’t step over this must be paid close attention to. Our recommended tests include an air pressure check to check the pressure your cement can with-hold by forcing air into your pipes to test the strength and a vacuum test to test your pipes strength by sucking the air out of the pipes with a vacuum.
Air Test
Raising the pressure of your pipes to 0.01 Bar to simulate the pressure of 100mm of water. You need to leave your airflow on to level for a few minutes. When the pressure drops, simply refill the lost space with more air. Use a notepad to graph the pressure changes every five minutes.
Vacuum Test
Next on the list is vacuum were similar to the first test you remove air from inside the pipes making sure it stays at 2.0 bars for around 10 minutes. Usually, afterward, we set the pipes to 5.0 bars for ten minutes to ensure no leakage after installation.
Note: Skipping these tests should never be done as the amount of damage leaking pipes can do can go from minor to expensive, you don’t want that.
Conclusion
I hope you got the information you need about how to install concrete rings. It’s important to remember to do all by regulations and most importantly, safely.
The concrete rings can be quite heavy so it’s best to use machines for moving them, if possible. As always, the key to success is to use proper tools for the job to have it done as effortlessly as possible. That applies from excavation to installation.
After everything is done, it’s still good to give the structure a little test so you know it will work as it should.
