Rehabilitation of Water Network in Khyiam Village

Please refer to the Terms of Reference (ToR) attached for the full details.

TERMS OF REFERENCE

Oxfam is a global movement of people who are fighting inequality to end poverty and injustice. Across regions, from the local to the global, we work with people to bring change that lasts.

OVERVIEW

Title and brief description of the requirement

Contracting Services for the Rehabilitation of the Water Network in Khyiam Village, Marjeyoun District

Delivery location

Khyiam Village

Contract start date

19 December 2025

How to apply

Interested candidates are invited to submit:

1. A quotation describing services and the financial offer.

See section ‘4. Application Process’ for further details

Deadline for submission of offers

12 December 2025

Specific considerations

A mandatory site visit will take place on 5 December 2025

1. BACKGROUND AND CONTEXT

Oxfam is a global movement of people, working together to end the injustice of poverty. Oxfam has been working in Lebanon since 1993. We provide humanitarian assistance to vulnerable people affected by conflict, and we promote economic justice and good governance, and women’s rights. Oxfam also works with local partners to contribute to the protection and empowerment of marginalized women and men.

2. SPECIFICATION OF GOODS and any SERVICES/ WORKS REQUIRED

The main objective of this intervention is to replace approximately 900 meters of deteriorated HDPE pipeline with new high-quality HDPE pipes and to ensure complete reinstatement and safe operational performance of the water distribution system in Khyiam Village, Marjeyoun District. The contractor shall perform all works related to the full rehabilitation of the water distribution pipeline, including but not limited to:

• Controlled excavation
• Pipeline removal
• Supply and installation of new HDPE pipes 63 mm
• Installation of valves, fittings, and accessories
• Construction of RC manholes
• Backfilling and compaction
• Asphalt reinstatement
• Testing and commissioning
• Documentation and as-built drawings

The objective is to deliver a fully functional, leak-free, safe, and durable water distribution network.

1. 1. SITE MOBILIZATION

Mobilization Requirements

The contractor shall mobilize all necessary resources, including:

• Excavators, compactors, vibratory rollers
• Trucks for soil removal and material delivery
• Welding machines (butt-fusion & electrofusion)
• Surveying tools (levels, total station, tape measures)
• Temporary storage and secure material zones
• Safety equipment: PPE, barriers, traffic cones, steel plates, warning lights

Site Preparations

Contractor shall:

• Establish site boundaries and install protective fencing
• Prepare access routes for workers and machinery
• Allocate safe storage for pipes, fittings, and reinforcement
• Perform a full walk-through with the supervising engineer
• Identify existing underground utilities with SLWE and municipality.
• Prepare an emergency response and hazard mitigation plan

Traffic & Public Safety Measures

• Install barriers, reflective tapes, metal plates at crossings
• Assign a traffic controller/flagman for busy roads
• Ensure 24-hour visibility of work zones with lights and signage
• The Contractor shall set out excavation lines and depths accurately before starting works.

No construction activity may start before safety approval is granted from Oxfam engineer.

1. 2. EXCAVATION & TRENCHING

Asphalt Saw-Cutting

• Saw-cut edges shall be perfectly straight using mechanical cutters.
• Depth of cut must fully penetrate the asphalt layer to prevent peeling or cracking.
• Removed asphalt shall be stacked separately for disposal.

Trench Width Requirements

• Minimum width: 40 cm
• Preferred working width: 50–60 cm (recommended for welding room & compaction)

If utilities are encountered, trench width may be increased upon engineer approval and site requirement.

Trench Depth Requirements (Final average depth ≈ 80 cm)

Depth layers:

• Bedding layer: 20 cm
• Pipe OD: 6.3 cm
• Surround layer above pipe: 20 cm
• Backfilling: approximately 34 cm of soil cover placed above the surround material (in two compacted layers).

Excavation Procedure

• Excavation must proceed in segments not exceeding 25–40 meters per time to maintain safety and avoid prolonged open trenches.
• Shoring or trench boxes must be used where soil is weak or deep.
• The trench bottom must be leveled and free from rocks, debris, and hard objects.

Handling of Excavated Material

• Contractor shall assess excavated soil quality.
• Reusable soil shall be stored on the side of trench.
• Contaminated or unsuitable material must be transported to a certified dumpsite.

1. 3. REMOVAL OF EXISTING PIPELINES

Removal Requirements

• Remove approximately 900 m of old/damaged HDPE pipes.
• Disconnect pipe ends carefully to avoid damaging existing fittings.

Trench Preparation

After pipe removal:

• Remove roots, stones, debris
• Level the trench
• Compact any loose spots
• Ensure trench is ready for bedding

1. 4. PIPE SUPPLY, ACCESSORIES & INSTALLATION

Pipe Supply (Detailed Requirements)

• Diameter: 63 mm (2.5-inch)
• Material: HDPE PE100 – PN16
• Color: black
• Standards: ISO 4427-2, EN 12201
• Delivered in straight lengths or coils (manufacturer recommended)

All pipes must be: be new and unused, stored in shaded areas to prevent UV damage, and protected from deformation

Connection to Existing Water Network

Contractor shall:

1. Locate the existing pipelines.
2. Expose them safely by manual excavation.
3. Clean the pipe exterior before connection.
4. Verify size compatibility and pipe condition.
5. Install reducers, couplers, or tapping tees as required.
6. Perform electrofusion welding to create a leak-free joint.
7. Coordinate shutdown times with the SLWE and municipality.
8. Flush the line before reopening supply.

Bedding Layer ; 20 cm

• Must be placed uniformly
• Compaction: light hand compaction only
• size should of 4.75mm-fine to small gravel,

Pipe Laying Requirements

• Pipes must rest fully on bedding without voids.
• No forced bending allowed radius per manufacturer.
• Ensure continuous alignment.

Surround Layer; 20 cm

• Must fully cover and protect pipe
• Same material as bedding
• Compact lightly with hand tools

Warning Tape

A detectable plastic warning tape is installed 30 cm above the pipe crown.

Welding & Jointing

Welding and jointing using electrofusion requires scraping the pipe surface, wiping it with alcohol, securing it with alignment clamps, and recording the barcode data. It also involves logging all welding parameters to ensure proper installation and quality control.

End Caps

HDPE PN16 end caps must be installed at all termination points and welded using electrofusion. They are required before pressure testing and must be clearly marked in the as-built drawings for any future extensions.

1. 5.  MANHOLE CONSTRUCTION

Reinforced Concrete Manholes – Internal Size: 70 × 70 × 80 cm (size may varies per site conditions)

Location

• Locations to be determined by Oxfam engineer and SLWE representative

Blinding

• Lean concrete 5–7 cm C10/C12
• Provides clean base for manholes construction

Structural Concrete

• Base slab: 15-20 cm thick
• Walls: 15 cm thick
• Cover slab: 10 cm
• Concrete grade: C25/30

Reinforcement

• Walls: Ø12 @ 20 cm both ways
• Slabs: Ø12 @ 20 cm both ways
• Minimum cover: 30 mm
• Steel Grade: 420 MPa

Manhole Accessories

Manhole accessories include a 75×75 cm ductile iron cover with an H-20 load rating, along with internal fittings, valves, and bends as required

Finishing

Finishing works include smoothing the internal walls, sealing pipe penetrations with mortar, and waterproofing all joints

1. 6. BACKFILLING & COMPACTION

Backfill Material

• Granular fill or crushed material
• Max particle size: 75mm
• Free of clay, organic matter, debris, and oversized stones
• In accordance with Ministry of Public Works Decree 13495/1998

Layering

• First backfill layer: 15 cm, compacted to 95% MDD
• Second backfill layer: 15 cm, compacted to 95% MDD

1. 7. ASPHALT REINSTATEMENT

Asphalt

Asphalt works include a 6–8 cm single-layer asphalt (depending on site conditions), using bitumen grade 60/70 with an MC-70 underco (or approved equivalent)

Compaction

Compaction must ensure a smooth finish aligned with existing road levels, with no visible settlement or surface irregularities.

1. 8. HYDRAULIC TESTING

Pressure Testing

• Conducted BEFORE final backfilling
• Pressure according to PN16
• Measure pressure drop (must be within limits)
• Submit signed pressure test certificate

1. 9. DOCUMENTATION

Contractor must submit:

Drawings

• Shop drawings
• Surveying and setting-out drawings
• Manhole detailed drawings
• As-built drawings (coordinates, depths, fittings, valves, end caps)

Material Approvals

• HDPE pipes
• Electrofusion fittings
• Asphalt mix
• Sub-base materials

Final Documentation

• Completion report
• Photo documentation before, during, and after works

1. 10. General Terms:
2. The Contractor’s relationship will directly be with OXFAM staff.
3. An Oxfam staff or a representative will be responsible to inspect and confirm the work.
4. The contractor must be capable of completing this task within 14 days.
5. Oxfam has the right to increase or decrease quantities at the same unit cost.
6. Any item not complying with the specs will be rejected.
7. The Contractor is responsible for any damage during works, including trees and utilities, and shall reinstate all affected assets at his own cost.