Drainage Contractor in Sri Lanka — Complete Guide to Drainage Systems

Drainage Contracting in Sri Lanka

Effective drainage protects buildings, roads, and infrastructure from flooding, erosion, and contamination. A qualified drainage contractor in Sri Lanka designs and installs systems that comply with national and international standards.

Types of Drainage Systems

Surface Water (Stormwater) Drainage

• Road gullies and gratings
• Open channels and culverts
• Soakaways and infiltration trenches
• Retention and detention tanks

Foul Water (Sewer) Drainage

• Sanitary sewer lines
• Manholes and inspection chambers
• Septic tanks and soakage systems
• Sewage pumping stations

Infrastructure Drainage

• Highway and carriageway drainage
• Bridge and culvert drainage
• Industrial site drainage
• Airport and port drainage

Cast Iron Manhole Covers & Grating Covers

HAMS Engineering manufactures cast iron manhole and grating covers to BS EN 124 in all load classes:

| Load Class | Test Load | Application | |-----------|----------|-------------| | AA | 670 kN | Airport / docks | | A15 | 15 kN | Pedestrian only | | B125 | 125 kN | Car parks, driveways | | C250 | 250 kN | Kerbside, road shoulders | | D400 | 400 kN | Roads, highways | | E600 | 600 kN | Heavy traffic, ports | | F900 | 900 kN | Aircraft, extreme loads |

Design Standards

• BS EN 124 — manhole cover load classes
• BS EN 12056 — gravity drainage systems
• BS EN 752 — sewer and drainage networks
• SLS standards — Sri Lankan drainage codes

Installation Process

1. Survey & design — levels, gradients, catchment
2. Excavation — trenching, shoring, dewatering
3. Bedding — granular or concrete base
4. Laying — pipework with correct fall (min 1:60 foul, 1:100 surface)
5. Manholes — chambers at junctions and changes of direction
6. Cover installation — correct load class for traffic
7. Testing — water or air pressure test
8. Backfill & reinstatement

Common Problems

• Insufficient gradient — blockages and standing water
• Wrong cover load class — cracking under traffic
• Poor jointing — root ingress and leakage
• No maintenance access — blockages inaccessible
• Inadequate capacity — flooding in heavy rain

Contact HAMS Engineering

HAMS Engineering is a CIDA registered MEP and infrastructure contractor (PV 00267372) offering drainage design, installation, and BS EN 124 manhole and grating covers manufactured in Sri Lanka.

📞 +94 76 066 0861

📧 info@hhkplumbing.com

Contact HAMS Engineering for drainage systems and cast iron covers across Sri Lanka.