Revised Laws of Saint Lucia (2023)

PART 3
DRAINAGE

4.   Layout of System of Drainage

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   (1)   Where the system of drainage is to connect to a lateral drain or to a septic tank or, in the case of surface water, where it is to connect to a watercourse or soakaway the drain shall be laid from the point of connection in a straight line to a manhole near the building and within its curtilage located conveniently for the reception of soil and waste water or for the reception of surface water and the drain shall continue beyond such manhole in a straight line to any further manhole or manholes which may be necessary effectively to receive from the building and its curtilage the whole of the soil and waste water or the whole of the surface water not required to be stored for use. Where the system is for the drainage of foul water, provision must be made as hereinafter specified for the ventilation of the drain at or near the end or ends remote from the lower end of the drain.

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   (2)   Where the system is to connect to a lateral drain which has no convenient junction already provided a manhole must be provided on the lateral drain at the point of connection to the drain.

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   (3)   Where the site coverage is such that the owner's outfall manhole cannot conveniently be within the curtilage of his or her property the Sewerage Authority may agree to the construction of this manhole within the public space.

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   (4)   No connections shall be made between systems of drainage dealing with foul water and systems of drainage dealing with surface water.

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   (5)   When the dual system of drainage is adopted:

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      (a)     the soil shall generally enter the drain, if above the ground floor by soil pipes and if at the ground floor by drains both connected directly to the nearest suitable manhole;

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      (b)     waste water shall generally enter the drain if above the ground floor by waste pipes and or waste water pipes discharging into collecting heads on waste water pipes, or connected directly to waste water pipes which discharge over or into gully traps connected to the drain and if at ground floor by discharging over or into gully traps, and thence by pipes connected directly to the nearest suitable manhole;

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      (c)     surface water from above ground floor shall by a suitable arrangement of rain water pipes, be discharged into open channels connecting to road drains or soakaways. No open channels will be permitted to cross public footpaths. Such crossings must be piped and the pipes laid at sufficient depth to allow the footpath surfacing to be carried over the pipe.

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   (6)   Where the one pipe system of drainage is adopted:

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      (a)     soil and waste water shall generally discharge into the soil pipe if the connection is 12 inches or more above the invert of the connecting drain below ground level, and if not, soil shall discharge directly into the drain and waste water indirectly into the drain by discharging over and into gully traps connected to the drain;

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      (b)     the destruction of the water seal of fittings required to be trapped as hereinafter specified, shall be guarded against by the use of approved deep seal traps. A trap having a water seal of not less than 3 inches shall be deemed to be a deep seal trap for the purpose of this Act.

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   (7)   No waste water pipe, soil pipe or ventilating pipe shall be trapped but all waste pipes connecting thereto shall be trapped effectually at the sanitary fitting by a trap so constructed as to be capable of maintaining a sufficient water seal.

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   (8)   Every branch drain shall at the point of junction join a main drain obliquely in the direction of the flow of such drain and all bends and turns shall be truly curved and any alteration in the size of the pipe shall be properly tapered and of good shape. Junctions shall wherever practicable be crown to crown.

5.   Construction of Drainage Works

Drains shall consist of pipes and channels laid true to line and levels and provided with all necessary bends, tapers and junctions to permit of the contents flowing at a self-cleansing velocity without settlement or scour to the outfall. The pipes shall be watertight and where they pass under a building they shall be of cast iron or shall be surrounded with concrete 6 inches in thickness save that where any pipe passes through any wall or beam it shall be protected against any settlement of such wall or beam by being separated therefrom with a gap of 3 inches which gap shall be unoccupied or shall be closed with a material which is incapable of transmitting an excessive load.

6.   Requirements as to Drainage Pipes

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   (1)   Pipes used for drains shall comply with the following requirements—

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      (a)     the pipes shall be of adequate size. Where used for the conveyance of foul water they shall be 4 inches in diameter except where the Sewerage Authority requires the use of pipes of larger diameter;

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      (b)     the pipes shall be laid to even falls between manholes to gradients normally of 1 in 40 and not steeper than 1 in 10 provided always that the Sewerage Authority may agree to a flatter gradient;

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      (c)     the pipes shall be laid with the barrel of the pipe resting on a good solid and even bed free from irregularities with any projecting socket sunk below the foundation if—

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         (i)     if an even bed cannot be formed in the natural earth the pipes must be laid on a bed of concrete 4 inches in thickness under the barrel and 8 inches wider than the external diameter of the pipe,

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         (ii)     if the pipe has less than 3 feet of cover and forms a part of a system connected to a public sewer it shall be surrounded with concrete 6 inches in thickness: Provided always that where cast iron pipes are used the Sewerage Authority may waive the requirements of this subparagraph.

7.   Jointing of Pipes Used for Drains

The jointing of pipes for drains shall be as follows—

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   (1)     Spigot and socket stoneware pipes or spigot and socket spigot and concrete pipes shall be brought up tight together and held concentrically with 3 or more turns of tarred spun yarn and the remainder of the joint shall be filled flush and bevelled off clear of the pipe angle of 60 degrees with mortar. Any excess mortar shall be removed from the inside of the pipe with a half round scraper.

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   (2)     Ogee concrete pipes shall have the ogee joint covered with mortar and the pipes shall be brought up tight together. A mortar fillet half an inch thick and 4 inches wide shall be placed centrally about the outside of the joint for the full perimeter of the pipes and any excess mortar shall be removed from the inside of the pipe with a half round scraper, provided always that where the pipes are to be surrounded with concrete the fillet may be omitted.

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   (3)     Where Stanton Cornelius jointed pipes are used a suitable rubber ring shall be placed at the spigot end of one of the 2 pipes to be jointed and the 2 pipes shall be pushed tightly home by hand, by the use of jacks or by the use of sylvesters whichever method is the most convenient.

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   (4)     Cast iron spun and steel spigot and socket pipes shall be brought up tight together and held concentrically with 3 or more turns of tarred spun yarn and the remainder of the joint shall be filled flush with molten lead or lead wool caulked home and finished ¹/₁₆ of an inch inside the socket.

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   (5)     The flanges of cast iron pipes shall be brought together with a suitable insertion between the flanges which shall then be securely bolted together.

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   (6)     The asbestos cement pipes shall be brought together with a suitable rubber ring on both ends and a detachable cast iron joint shall be securely bolted in position and shall be encased with bitumen. Alternatively a suitable asbestos cement sleeve may be rolled into position over the 2 rubber rings.

8.   Requirements as to soil, ventilating and waste pipes

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   (1)   Pipes used for soil pipes, ventilating pipes and waste water pipes shall comply with the following requirements—

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      (a)     soil ventilating pipes shall be of adequate size and shall be 4 inches in diameter except where the Sewerage Authority requires the use of pipes of larger diameter;

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      (b)     anti-syphonage pipes to traps of water closets, slop sinks, lavatory basins, sinks, urinals and all other sanitary fittings shall be a minimum of 2 inches in diameter and connected to a soil and ventilating pipe at least 3 feet above the highest soil or waste water connection to such soil and ventilating pipe or carry up as for a bent pipe as described in subparagraph (c) of paragraph (1) of this regulation and in paragraph (3) of regulation 16;

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      (c)     the pipes shall be securely fixed at intervals not exceeding 4 feet to the walls of the building or to other suitable support. Where a pipe is to be used either wholly or partially as a ventilating pipe it shall be extended to such a height as effectually to prevent any escape of foul air from such pipe into any building in the vicinity thereof and in no case to a less height than 3 feet above the eaves of any adjoining roof or to less height than 3 feet above the top of any window, door or ventilator which shall be within an unobstructed distance of 20 feet horizontally from the open end of such pipe. The open end of any ventilating pipe shall be provided with an approved balloon.

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   (2)   Cast iron spigot and socket pipes shall be brought up tightly together and held concentrically with 3 or more turns of tarred spun yarn and the remainder of the joint shall be filled flush with molten lead or lead wool caulked home and finished ¹/₁₆ of an inch inside the socket.

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   (3)   Asbestos cement pipes shall be brought up tightly together and held concentrically with tarred spun yarn and pointed with mortar.

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   (4)   Where any lead waste pipe is required to connect to any metal or fireclay pipe or fitting the joint shall be made with a suitable brass socket or ferrule the junction of the lead pipe to the socket or ferrule being by means of an efficient wiped joint and the junction of the socket or ferrule with an iron pipe being by means of a caulked lead joint and the junction of the socket or ferrule with a stoneware pipe being by means of mortar.

9.   Requirements as to rainwater pipes, gutters and fittings

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   (1)   Pipes used for rainwater pipes and gutters and fittings in connection therewith shall comply with the following requirements—

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      (a)     the pipes and gutters shall be of adequate size to prevent any over-flowing or surcharging and shall not in any case be less than 2 square inches of effective cross sectional area of gutter per hundred square feet of roof drained;

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      (b)     the gutters shall be securely fixed to the building at intervals not exceeding 3 feet and shall generally be laid at a gradient of 1 in 120 in the case of eaves gutters and 1 in 80 in the case of valley and parapet gutters. Gutters shall discharge into rainwater pipes so placed that not more than 30 feet of gutter enters the rainwater pipe from any one direction.

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   (2)   Cast iron pipes, gutters and fittings shall be brought tightly up together and jointed with tarred spun yarn and red and white lead putty.

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   (3)   Asbestos cement pipes, gutters and fittings shall be brought tightly up together and jointed with mortar or with approved bituminous compound.

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   (4)   Pressed steel pipes gutters and fittings shall be either of the pressed type where a spigot enters a socket and socket and spigot are securely bolted together or the strapped type where 2 spigot ends bedded on red lead butt over a 4 inch long strap to which both spigots are bolted.

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   (5)   Aluminium gutters shall be brought tightly together and jointed with red and white lead putty.

10.   Connection of Soil Pipes to Drain

The soil pipe shall be connected to the drain without a trap by means of a bend of the same material as the drain and such bend shall be surrounded with concrete 4 inches thick. An airtight access hatch shall be provided near the foot of the soil pipe in all cases where the soil pipe is situated at a distance greater than 10 feet from the manhole to which it first connects.

11.   Connection of Soil Fitments to Soil Pipes

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   (1)   Soil fitments connected to the soil pipe shall have water seals 2 inches deep where the inlet has an internal diameter of not less than 3 inches and 3 inches deep where the inlet has an internal diameter less than 3 inches.

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   (2)   The traps to water closet pans shall be ventilated where and in manner required by regulation 16(3).

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   (3)   The connection shall not have any bend or angle except where unavoidable in which case the bend or angle shall be as obtuse as possible and shall not reduce the internal diameter of the pipe.

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   (4)   The materials forming the connection shall conform to the requirements for materials forming soil pipes.

12.   Waste Pipes

A pipe used for a waste pipe shall comply with the following requirements—

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   (a)     it shall discharge so as not to cause dampness in a wall or foundation or floor of a building;

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   (b)     if it discharges to a drain otherwise than by a soil pipe it shall be disconnected from the drain by a gully trap;

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   (c)     it shall be provided with a suitable trap at its junction with the waste water fitting;

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   (d)     if it discharges into a soil pipe it shall be provided with a suitable trap adequately secured against destruction of the water seal. A trap having a water seal of not less than 3 inches and ventilated where and in manner required by regulation 16(3) shall be deemed to be adequately secured against the destruction of the water seal for the purpose of this Act.

13.   Gully Traps

Wherever practicable gully traps shall be located outside buildings and shall be fitted with an approved movable grating or cover and shall if located at ground level be protected against the ingress of surface water by a sufficient kerb. The outlet of the gully trap shall not be of less diameter than 4 inches.