Cement concrete structures corrode in H2S environments. So why install a corrodible manhole in a system that is deemed corrosive? Simply stated, with polymer concrete, you get completely inert structures. Now the industry has a solution to break the cycle of corrosion. No more band-aid coatings or liners.
Manhole Classifications:
Manholes and inspection chambers are mainly classified are as follows
- Inspection Chambers
- Type 1 manholes
- Type 2 manholes
- Type 3 manholes
Inspection chambers:
| S/N | ID No. | Manhole DIA (mm) | Pipeline DIA (mm) | Depth range (m) |
|---|---|---|---|---|
| 1 | T1-0.6 | 600 | Up to 200 | 1.5 |
| 2 | T1-0.8 | 800 | Up to 200 | 1.85 |
| 3 | T1-1.0 | 1000 | Up to 200 | 3 |
Type 1 Manholes:
| S/N | ID No. | Manhole DIA (mm) | Pipeline DIA (mm) | Depth range (m) |
|---|---|---|---|---|
| 1 | T1-1.2 | 1200 | Up to 400 | 4 |
| 2 | T1-1.5 | 1500 | Up to 400 | 5 |
| 3 | T1-1.8 | 1800 | Up to 900 | 5 |
| 4 | T1-2.0 | 2000 | Up to 1000 | 6 |
| 5 | T1-2.2 | 2200 | Up to 1400 | 6 |
| 6 | T1-2.4 | 2400 | Up to 1600 | 6.5 |
| 7 | T1-2.8 | 2400 | Up to 2000 | 8 |
Type 2 manholes:
| S/N | ID No. | Manhole DIA (mm) | Pipeline DIA (mm) | Depth range (m) |
|---|---|---|---|---|
| 1 | T2-1.5 | 1500 | Up to 500 | 20 |
| 2 | T2-1.8 | 1800 | Up to 900 | 10 |
| 3 | T2-2.0 | 2000 | Up to 1000 | 11 |
| 4 | T2-2.1 | 2100 | Up to 1400 | 10 |
| 5 | T2-2.2 | 2200 | Up to 1400 | 10 |
| 6 | T2-2.4 | 2400 | Up to 1600 | 11 |
| 7 | T2-2.8 | 2800 | Up to 2000 | 12 |
Type 3 manholes:
| S/N | ID No. | Manhole DIA (mm) | Pipeline DIA (mm) | Depth range (m) |
|---|---|---|---|---|
| 1 | T3-1.8 | 1800 | Up to 900 | 20 |
| 2 | T3-2.1 | 2100 | Up to 1400 | 20 |
| 3 | T3-2.2 | 2200 | Up to 1400 | 15 |
| 4 | T3-2.4 | 2400 | Up to 1600 | 19 |
| 5 | T3-2.8 | 2800 | Up to 2000 | 25 |
Type 4 manholes:
| S/N | ID No. | Manhole DIA (mm) | Pipeline DIA (mm) | Depth range (m) |
|---|---|---|---|---|
| 1 | T4-2.1 | 2100 | Up to 1400 | 30 |
Manhole Units:
Types of units are described as follows
- Height adjusting unit or compensation unit: – Used to adjust the manhole height up to the ground level. Also can be designed as per DI cover design
- Cover slab: – The cover slab shall be generally with 600mm opening for all manholes.
- Chamber Ring or shaft ring: – Chamber ring shall be of various diameter and heights as per design.
- Reducing slab or Adaptor plate: – Used to reduce the shaft diameter of type 2 and type 3 manholes.
- Base slab: – Base slab holds the total weight of manhole including traffic load, and it will varies with diameter and thickness as per design
Joint Configuration Properties of Polymer Concrete Manholes and chambers:
Leak-tightness of manholes and their joints tested as per BS EN 14636-2
Exfiltration:
Withstands an internal pressure of 1 bar for 15 minutes without any sign of leakage, damp patches or water droplets.
Infiltration:
Withstands an internal negative pressure of 0.8 bar for 15 minutes without any damage to its components nor exhibit specified change in pressure.
Properties of polymer mortars
Polymer mortar contains high amount of resin which gives great adhesive property.
- Density – 2.35 Ton/ M3
- Compatibility – Compatible to bind between polymer concrete, GRP ,uPVC ,Clay and Concrete pipes
Advantages of polymer concrete manholes:
- Rapid curing at ambient temperatures.
- High tensile, flexural, and compressive strengths.
- Good adhesion to most surfaces like any pipe connections.
- Good long-term durability with respect to freeze and thaw cycles.
- Low permeability to water and aggressive solutions.
- Good resistance against corrosion.
- Adaptable for quick and easy installation methods.
- Compatible for many possible modification with less effort.
Applications:
- Sewer system both urban and industrial
- Pumping stations
- Industrial waste
- Seashores
- House connection chambers
