Khumbulani combined school: construction of new sanitation infrastructure and associated external works (CIDB 5gb or higher)

Scope

• Construction of new sanitation infrastructure and associated external works at Khumbulani Combined School for the KwaZulu-Natal Department of Education, executed through the Department of Public Works.
• Contract period: 10 calendar months.
• Pricing is by bill of quantities; the tenderer enters rates and amounts against each measured item.
• Work is measured under the Model Preambles for Trades (2008 Edition) and the Standard System of Measuring Building Work.

Section 2 — Alterations

• Demolish two existing single-storey ablution buildings (7.5m x 3.5m and 2.77m x 4m on plan, 3m to eaves), including removal of internal sanitary fittings and desludging and decommissioning of the existing ablution blocks.
• Break up and set aside existing concrete surface bed or slab for filling: 15 m3.
• Surplus demolition material used to fill existing toilet pits: 15 m3.
• G7 material placed in 200mm layers compacted to 93% Mod AASHTO in the toilet pits: 175 m3.
• A desludging certificate must be provided before payment is released for demolition of the toilets.
• Remove and relocate three existing container ablutions (3.00 x 6.41m) to a location indicated by the Department of Education.
• Temporary shade cloth screen, 2000mm high, 70% green shade cloth with posts and fixings: 297 m.
• Two temporary double swing gates, 5000mm wide x 2400mm high, for construction vehicles.
• Old materials become the contractor's property and a credit must be allowed in the final summary; all old material and rubble must be carted away regularly and not allowed to accumulate; no old material may be reused unless specifically described for reuse.
• Materials described for handing over must be stored and an official receipt obtained; failure to produce the receipt on request leaves the contractor liable for full replacement value, deducted from monies due.

Section 3 — Prototype 4A-F

Earthworks

• Strip an average 100mm layer of topsoil and stockpile on site: 110 m2.
• Excavation in earth: reduced levels under floors 1 m3; raft foundation 14 m3; holes (pits) 144 m3.
• Excavation in strata of a more difficult character: soft rock 17 m3; hard rock 47 m3.
• Cart away surplus material to a dumping site located by the contractor: 124 m3.
• Risk of collapse of excavation sides: trenches and holes not exceeding 1.5m deep 36 m2; exceeding 1.5m and not exceeding 2m deep 78 m2.
• Keep excavations free of water.
• Earth filling from excavations in prescribed stockpiles on site: 27 m3.
• Backfilling to trenches and holes, compacted to 93% Mod AASHTO: 83 m3.
• G5 earth filling supplied by the contractor, compacted to 93% Mod AASHTO: under floors, steps and pavings 26 m3; to sides of pits 39 m3.
• Coarse river sand filling supplied by the contractor under floors: 3 m3.
• Compaction of ground surface under floors, including scarifying 150mm, breaking down oversize material and compacting to 95% Mod AASHTO: 138 m2.
• Prescribed density tests: 28 Mod AASHTO density tests and 28 field density tests including optimum moisture content (four readings per test).
• Soil insecticide: under floors including shallow furrows against foundation walls 83 m2; to bottoms and sides of trenches 131 m2.

Concrete, formwork and reinforcement

• 15MPa/20mm concrete blinding under footings and bases: 1 m3.
• 25MPa/20mm concrete: strip footings 3 m3; ramps and aprons 2 m3; bases 6 m3; raft foundation 11 m3.
• Smooth formwork (degree of accuracy 1): edges, risers, ends and reveals not exceeding 300mm 53 m; sides of raft foundation 36 m2; suspended slabs including propping not exceeding 3.5m high 29 m2; 230 x 350mm beam below suspended slab 6 m2; 250mm diameter openings 8 No; 110mm diameter openings 8 No.
• Wood trowel finish to top of surface beds and slabs: 80 m2.
• Sikafloor-Curehard-24 dry-shake floor hardener applied during power floating: 45 m2.
• Concrete strength test cubes: four sets of six 150 x 150 x 150mm cubes delivered to an approved laboratory, all charges paid (provisional).
• Movement joints: 6 x 20mm deep saw cut joints in concrete 10 m; 10mm isolation joints with softboard between concrete and brick 28 m and 6 m2.
• Reinforcement (provisional): high tensile steel bars all sizes 3 t; Type 245 fabric reinforcement in surface beds and slabs 86 m2.
• Concrete cube testing must be done by an independent firm or institution nominated by the contractor and approved by the architect.

Precast concrete

• Precast concrete pit latrine access panels, 100mm thick, with concealed key holes and seals: 2020 x 375mm 2 No; 1295 x 375mm 2 No; 1025 x 375mm 2 No; 1100 x 375mm 2 No; 1040 x 375mm 8 No.

Masonry

• NFX bricks (14 MPa nominal compressive strength) in class 1 mortar: piers 2 m3; half brick walls 4 m2; one brick wall to pits 86 m2.
• NFP bricks in class II mortar: half brick walls 23 m2; half brick wall in beamfilling 5 m2; piers 4 m3; one brick walls 133 m2.
• Corobrick Firelight Satin FBX facing bricks with 6mm square recessed joints: extra over ordinary brickwork in stretcher bond 123 m2; face brickwork in beamfilling 5 m2; face brick on edge window cill 6 m; cut soldier course window head 16 m; soldier course band 160mm wide 7 m; fair raking cutting 11 m.
• Bagging with 1:3 cement and sand to receive bitumen paint: 98 m2.
• Brickwork reinforcement built in horizontally: 75mm wide 135 m; 150mm wide 1820 m.
• Concrete prestressed fabricated lintels 110 x 75mm: lengths not exceeding 3m 16 m; not exceeding 4.5m 49 m.
• Galvanised hoop iron cramps 30 x 1.6mm, 500mm long: 22 No.
• Samples of all masonry building units must be submitted, minimum six units.
• Blockwork must comply with SABS 1215 and SABS 0145; joints to surfaces to be plastered raked out at least 10mm.

Waterproofing

• 375 micron Consol Plastics Brikgrip DPC embossed damp proof course in walls: 21 m2.
• 250 micron Consol Plastics Gunplas USB Green waterproof sheeting sealed at laps with Gunplas pressure sensitive tape: raft foundation 74 m2; under pit base slab 33 m2; pit floors 32 m2.
• One coat Sikafloor-156 and three coats Sikagard-63 N (or equally approved system) on external pit walls: 53 m2; internal pit walls 84 m2; pit slab 32 m2.
• 3mm Sikagard 720 EPOCEM on green or damp concrete plus one coat Sikafloor-156 to manufacturer's specification.
• Two coats Brixeal bitumen emulsion waterproof coating on bagged brick walls: 98 m2.
• Sealants: silicon pointing to aluminium windows 41 m; Sikaflex PRO 2HP or equal in 6 x 10mm saw cut joints 14 m, 10 x 10mm isolation joints 40 m, 10 x 10mm construction joints 6 m.

Roof coverings and insulation

• Safintra 0.50mm Widedek AZ150 G550 pre-painted interlocking roof sheeting fixed to 75 x 50mm SA pine purlins at 1200mm centres with two galvanised hurricane clip screws at each intersection, to premanufactured gang nail trusses: pitches not exceeding 50 degrees 71 m2.
• 0.5mm ridge capping 10 m; 0.5mm cover flashing 375mm girth twice bent 20 m; purpose-made tile to ridge end 4 No; flashing around 110mm pipe with fibreglass and resin 8 No; moulded rib polyethylene filler blocks 35 m.
• Sisalation 420 heavy industrial grade aluminium foil insulation laid taut over purlins and fixed with the roof covering: 68 m2.
• Sondor eave polycloser: 42 m.

Carpentry and joinery

• Monoplaner prefabricated connector plate roof trusses at maximum 1600mm centres, 25 degree pitch, suitable for Everite Nutec Bigsix corrugated sheeting with 50 x 76mm purlins at 1050mm centres and gypsum plasterboard ceiling: 11 No trusses, 5100mm span x 1100mm high with 450mm overhang both sides.
• Truss prices must include design, supply, wind category to SANS 10160 and erection, with bolts and connectors; actual measurements must be taken on site to match existing; permanent bracing and runners are included as an item.
• Sawn softwood: 38 x 114mm wall plates 31 m; 38 x 114mm bracing 35 m; 50 x 76mm bolted purlins 84 m.
• Structural timber: 45 x 145mm treated pine beams, ends treated with two coats Flintkote and built 200mm into brickwork: 10 m.
• Hurricane clips: 176 No.
• TR1 and TR2 certification of all trusses must be allowed for.
• Everite Nutec fibre cement barge boards 80 x 200mm including H-profile jointing strips: 13 m; fascia boards 15 x 225mm including PVC H-profile jointing strips: 21 m.
• SABS 545 solid core doors with vertical tongue and groove boarding both sides and hardwood edging, 44mm, 813 x 2032mm: 6 No.
• TDM hardwood doors with double top and bottom rails, tongue and groove boarding, ledges and braces, 44mm, 813 x 2032mm: 3 No.
• 108 x 44mm rebated timber door frames for 813 x 2032mm doors, retro-fixed to walls: 9 No.

Ironmongery

• 1.5 pairs 108mm brass butt hinges: 11 pairs.
• Union 2261-76SS four-lever upright lock with AL684-05AS lever furniture: 3 No.
• Union 2277-78SS three-lever upright lock with AL684-05AS lever furniture: 6 No.
• Facility indicator bolt code 37651RH: 9 No.
• Chairman Industries grab rails: DL3 stainless steel dogleg side rail with centre flange 1 No; SR5-500mm stainless steel flushvalve back rail 1 No.
• Lockable two-roll toilet roll holders: 8 No.
• Union AL684-05AS hat and coat hooks: 9 No.
• Union 87001SS door stops: 9 No.
• Door signs of grey high-impact acrylic, 200 x 70 x 2.5mm with 40mm letters, 1850mm above finished floor level (allow for 10 letters): 11 No.
• Paraplegic sign 150 x 150mm: 1 No; female sign WBH 2314 150 x 150mm white ABS with black engraved signage: 1 No.

Metalwork

• Hot dip galvanised steel windows, prices to include all glass, ironmongery, fixing and sealing: 533 x 654mm 8 No; 899 x 457mm 2 No.
• Hot dip galvanised burglar bars of 40 x 12mm EN8 flat steel framing with 19mm diameter EN8 horizontal bars at 138mm centres, drilled for 12mm expansion bolts: to suit 533 x 654mm openings 8 No; to suit 899 x 457mm openings 2 No.
• Standard pressed steel door frames, 1.2mm double rebated for one brick walls with crimped lugs and two 100mm galvanised loose pin hinges, for 813 x 2032mm doors: 9 No.
• Hot dip galvanised steel posts: 90mm diameter x 3mm wall circular stanchion with top closure, bracket and 250 x 250 x 3mm base plate set in 450 x 450 x 650mm deep concrete footing: 3 No.
• Hot dip galvanised channel: 149 x 49 x 5mm L channel fixed with 10 x 140mm expansion bolts at 600mm centres 5 m; 140 x 60 x 15mm U channel with 10 x 410mm expansion bolts at 600mm centres 5 m.
• Hot dip galvanised single gates, 877mm long x 2225mm high, rectangular hollow section frame with diagonal braces, bolt frame and three pin hinges: 2 No.

Plastering

• 30mm thick screeds: on floors and landings 47 m2; on pit base slab 33 m2.
• Cement plaster on brickwork: superstructure internal walls 185 m2; pit walls 99 m2; narrow widths not exceeding 300mm 3 m2.

Plumbing and drainage (provisional)

• uPVC rainwater goods (Marley Vynadeep or equal): 146 x 93mm half round eaves gutters 21 m; long-arm swan-neck 100mm bend combinations 4 No; stopped ends 4 No; outlets for 75mm pipe 4 No; 80mm diameter rainwater pipes 14 m; bends 8 No; shoes 4 No; spreaders for 75mm pipe 4 No.
• Sanitary fittings: Atlas VIP toilet with Atlas VIP 200 inlet funnel or equal 8 No; Atlas Viking handwash basin or equal 6 No.
• 40 x 40mm Flexitrap butyl rubber deep seal P or S traps jointed to waste outlet and PVC pipe: 6 No.
• Taps and valves: Cobra 15mm chrome plated elbow action raised nose pillar tap with blue indicator (Code 503-21B), SANS 226:2004 Type 2, 1 No; KM2 15mm pillar tap with blue inlay 7 No; 20mm stopcock 2 No.
• PVC pipes and fixing to walls, floors, roofs, slab soffits, chases and concrete: 40mm 18 m; 50mm 18 m; 110mm 65 m; 110mm stubstacks with PVC cap fixed to external walls 7 m.
• Extra over uPVC pipes for fittings: 40mm 15 No; 50mm 13 No; 110mm 19 No.
• Class 2 copper pipes with brass compression fittings and fixing: 20mm 35 m; 15mm pipe (quantity not stated in the available text).

Site conditions

• Trial holes indicate silty clay to approximately 500mm depth with fine to medium loose sandy material below; the water table is at a maximum depth of approximately 1000mm.
• A soils investigation report by the engineer is annexed to the bills of quantities; excavation descriptions include all ground classifiable as earth, with more difficult conditions measured separately.

CIDB

• Minimum grading: 5GB or higher.

Contract period

• 10 calendar months.

Measurement and standards

• Work is measured and priced under the Model Preambles for Trades (2008 Edition) and the Standard System of Measuring Building Work.
• Blockwork must comply with SABS 1215 and SABS 0145; concrete testing to SABS 1200 G.
• Roof trusses must be designed to SANS 10160 wind category and certified under TR1 and TR2.
• Taps must comply with SANS 226:2004 Type 2 (BS 5412).

Payment condition

• A desludging certificate must be submitted before payment for demolition of the toilets is released.