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Figure 6.2.1a.(1) : Provision of dry rising mains

Dry rising main (dry riser).- A vertical pipe installed in a building for firefighting purposes, fitted with inlet connections at fire engine access level and landing valves on various floors, which is normally dry but is capable of being charged with water usually by pumping from fire engine pumps.

Dry rising mains are basically dry water pipes. The empty mains need to be charged with water through the breeching inlets by fire fighting appliance. The dry rising mains should not exceed 60m to avoid excessive pumping pressure.

Generally, building with a small foot print and the riser stack is located at the perimeter wall of the building, there is no need to provide landing valve at 1^st storey level. However, if the riser stack is located deep inside the building as shown in Figure 6.2.1a.(1), then landing valve is required to be provided at 1st storey level.

Figure 6.2.1a.(3)

Where a block of residential building has podium and tower blocks integrated:

(1) Tower block exceeding 60m in habitable height shall be provided with wet rising main.

(2) Podium block needs to be provided with dry rising main only.

Figure 6.2.1b. - 1 : Rising mains in building of habitable ht. greater than 10m

Figure 6.2.1b. - 2 : Rising mains in building of habitable ht. 10m and less

All basements except those under PG I are required to be covered by dry rising main, irrespective of the depth and number of basements below ground level. Rising main would help to provide steady supply of water required by firefighters during emergency. The provision would eliminate the tedious process of laying fire hoses from ground level into the basement floors to tackle any outbreak of fire.

Where breeching inlets are provided at the foot of the riser stack, landing valve for PG II is not required to be provided at the 1^st storey level. 

Figure 6.2.1c. : Type of rising mains to be installed in high-rise buildings

1. For the purpose of determining the provision of rising main to an apartment or maisonette building, the habitable height shall be taken from the level of the lowest fire engine accessway or fire engine access road where breeching inlets are provided.

2. Dry rising mains are basically dry water pipes. The empty mains need to be charged with water through the breeching inlets by fire engines. The dry rising mains should not exceed 60m in height to avoid excessive pumping pressure.

3. Wet rising mains are constantly charged with water that provide the required flow rate and pressure for firefighting and equipped with water storage capacity for a given duration of 60 mins. The breeching inlets, usually provided at ground level, are meant for replenishing the water tank.

Figure 6.2.2a. - 1

All buildings with habitable height exceeding 10m would require one or more rising mains. All parts of the floor shall be within 38m from a landing valve.

Figure 6.2.2a. - 2

The provision of rising main shall be such that all parts of any floor are within 38m from a landing valve, measured along a route suitable for hose lines including any distance up or down a staircase.

Figure 6.2.2a. - 3 : 100mm minimum nominal bore rising main

The minimum nominal bore of a rising main shall be 100mm where the rising main does not exceed 45m in height and only one landing valve is provided at each floor.

Figure 6.2.2a. - 4 : 150mm minimum nominal bore rising main

The minimum nominal bore of a rising main shall be 150mm where the rising main either (i) exceeds 45m in height or (ii) is permitted to have two landing valves on any floor.

The height of rising main is the habitable height measured from the fire engine access level to the finished floor level of the topmost floor served by the rising main, irrespective whether or not the main is extended above roof level. The above figure shows two landing valves being installed in the top 2 floors though the height of rising main does not exceed 45m, the minimum nominal bore of the rising main shall not be less than 150mm. 

Figure 6.2.2b.(1) - 1 Rising main in fire lift lobby/smoke-stop lobby

Figure 6.2.2b.(1) - 2

Where rising mains is located within a protected lobby (smoke-free/fire lift lobbies), it need not be separately protected. However, if the rising mains is positioned or located within an unprotected areas/spaces, it shall be encased with a fire resistance enclosure. 

Figure 6.2.2b.(1) - 3

Figure 6.2.2b.(1) - 4

In the above situation (Figure 6.2.2b.(1) – 4) where the rising mains are located outside the staircases and along external exit passageway/external corridor which are naturally ventilated, there is no need to protect the rising main and landing valve separately, because the external exit passageway/external corridor is treated as ‘protected lobby’, for the purpose of interpretation and application of this requirement.

Figure 6.2.2b.(2) - 1 : Rising main outside protected staircase

Figure 6.2.2b.(2) - 2 : Rising main inside protected staircase 

The location of the rising main should not cause obstruction to the escape path inside the staircase.

1. Location of rising mains

The entire pipework and landing valves comprising each rising main system inside the building shall be confined:

a. within a ventilated lobby of a protected lobby approach stairway, where this is provided, or

b. in such other protected areas as may be agreed with the SCDF.

2. Rising mains shall be so located that they are protected against mechanical and fire damage.

3. No part of a rising main shall be placed in any shaft containing a gas, steam or fuel pipelines or electrical cables and wirings.

4. Where passing through other than protected area e.g. protected lobby shaft, pipe need to be encased or protected by and fire rating material with 2-hr fire resistance rating.

Figure 6.2.2c. - 1 : Example A - Block of flats/maisonettes

A single rising main is provided in  example A as the distance from the remotest point in any residential unit to the rising main landing valve, measured along the route of travel, does not exceed 38m.

Figure 6.2.2c. - 2 : Example B

Two stacks of rising mains are required in example B if the coverage or travel distance to the remotest point of the floor exceeds 38m.

Figure 6.2.2c. - 3 : Example C : Office/factory/warehouse block

A single rising main is provided in example C as the distance from the remotest point in any unit to the rising main landing valve, measured along the route of travel, does not exceed 38m.

Not Acceptable

Figure 6.2.2c. - 4 

The above figure shows rising main installed in the core of a building, meeting the requirements of distance coverage (38m). Such arrangement is deem not acceptable to the SCDF. The position of rising mains shall be located in the following areas (see Cl.6.2.2b.) in the order of priority.

Acceptable

Figure 6.2.2c. - 5

The above figure is an acceptable arrangement of positioning rising mains in the order of priority. Two stacks of rising main are required if the distance exceeds 38m, measured from the landing valve to the remotest point.

Figure 6.2.2c. - 6 

Where the pipe work and landing valve are located outside protected lobby or area allowed by the SCDF, they shall be protected by approved 2-hr fire-rated enclosures.

Provision of landing valve to any rising main for PG II at 1st storey is not required if any part of that storey is not more than 38m from the external wall of the building.

A landing valve with an instantaneous female coupling for connecting to SCDF’s 63.5mm diameter standard hose shall be provided for each rising main on every floor above the ground, including the 1st storey, every basement floor and on the roof for testing purposes. External walls refer to the external walls of the building that are facing or adjoining the boundaries. Where any part of the floor space in the building is less than 38m from the external wall, firefighters could connect multiple hose lengths to the fire pumper for the supply of water. As it is time consuming and laborious to connect additional multiple hose lengths, landing valve shall be provided to the rising mains at 1st storey if any part of the floor space in the building exceeds 38m from the external wall of the building.

Figure 6.2.3a.

(a) The breeching inlets would be located on the external wall of the building and to be within 18m of the fire engine accessway or fire engine access road. The breeching inlets shall be visible from the adjacent accessway.

(b) Thus, a fire engine accessway can serve more than one rising main to one or more buildings, provided (a) above is complied with.

( No illustration )

The inlets and the vertical run of the rising main shall be kept as short as possible. The total pressure loss of the dry rising main shall not exceed 6 bar based on the design water flow rate. This is to correspond with the maximum habitable height of 60m.

( No illustration )

1. For wet rising mains it is essential that pressures and flows be adequate at all times to serve the required number of jets likely to be used.

2. The water supply to the rising mains should be kept entirely independent of water supplies feeding other installations including those for other firefighting systems.

3. Means of supply for wet rising mains

a. Each wet rising main shall be fed from a suction or storage tank having a minimum effective storage capacity capable of supplying water at the rate of 27 L/s for a period of at least 30 minutes.

b. The storage tank(s) shall be automatically supplied either directly or indirectly via other tanks from a public main(s).  The pipe drawing water from public mains to the tank shall be at least 150mm in diameter.

c. Break tanks not serving as storage tanks shall have an effective holding capacity of not less than 11.5m³ for each wet rising main.

4. Water tanks for wet rising mains

Tanks supplying water for domestic purposes shall not be used as suction tanks for wet rising mains.

1. The minimum water supply flow rate shall be maintained in the wet rising system when 3 landing valves within the system are in the fully open position:

a. 27 L/s for a residential building.

b. 38 L/s for a non-residential and mixed occupancy building.

2. When more than one wet rising main is required in any zone in a building, the minimum common water supply shall be as stated below.  Where the total maximum supply rate exceeds those stated in (a) and (b), another common water supply system shall be used.

a. For a residential building, 27 L/s for each rising main.

b. For a non-residential or any mixed occupancy building 38 L/s for the first rising main and 19 L/s for each additional rising main, subject to a total maximum supply rate of 95 L/s for PG III, IV, V & VII buildings and 133 L/s for PG VI and VIII buildings.

( No illustration )

A minimum running pressure of 3.5 bar and a maximum of 5.5 bar shall be maintained at each landing valve when any number, up to three, are fully opened.

( No illustration )

1. To reduce the risk of hose bursting, arrangements shall be made in accordance with BS 5041: Pt 1 so that when the water is shut off at the nozzle the static pressure in any line of hose connected to a landing valve does not exceed 8 bar.

2. To dispose of excess flows and pressures over and above those required (i.e. when only one jet is in use) a pressure control valve shall be incorporated in the body of the landing valve which is then permanently connected into the relief pipe. This relief pipe should run throughout the length of the wet rising main installation and should terminate either back into the suction tank or to drain.

Figure 6.2.4e. - 1 : Wet rising mains system for building height exceeding 60m

1. The location and number of storage tank would be determined by the design of the wet rising main system and the height of the building. SS 575 should be fully complied with.

2. It is important that at early design stage of the building, the type of design of the wet rising main system should be drawn up to allow allocation of space for pumps and water tanks.

3. Usually, storage tanks and pumps are located in mechanical service floor in upper storey and basement, and on the roof of the building.

4. The capacity of break tank shall have an effective holding capacity of not less than 11.5m³ for each wet rising main.

Footnote:

(a) Storage tank is water tank having a minimum effective wet rising main storage capacity capable of supplying water at a given rate for a period of at least 30 minutes.

(b) Break tank is either (a) a tank into which the incoming supply connection from the PUB water mains discharge, or (b) an intermediate tank for limiting the system pressure.

(c) Suction tank is a tank from which a pump can draw water.

Figure 6.2.4e. - 2 : Fire hose cabinet detail

Wet rising mains system

1. “Wet rising mains” function similarly to dry rising mains. However, the pipes are permanently charged with water from a pressurised supply, and fitted with landing valves on various floors.

2. The breeching inlet act as an alternative means of supplying water to the rising mains system should the incoming public water supply pipes be damaged or the water supply is inadequate.

Figure 6.2.4f. : Example of pump room in basement

Pump room in basement

1. Pumps, which are part of the wet rising main system, must be properly protected from the effect of heat and fire. As pumps are the vital nerves of the system, they should be installed in room having the necessary fire-rated enclosures and door (min 2-hr fire resistance rating).

2. Pumps shall be selected to meet the design requirements of the rising main system and be listed by recognised institution such as UL or FM.

3. There should be a voice communication system to provide intercommunication amongst all pump rooms.

4. Mechanical ventilation and electrical lighting in the pump room shall be equipped with standby emergency power supply.

Standby hose provides the firefighter greater hose length connection in situation where the floor space is extensive. The hose from other floors could be transferred to fire floor quickly when required by firefighters. Standby hose shall be kept locked in a cabinet, when placed along escape corridor, in common area and circulation space. The hose is allowed to be left mounted on hook or cradle inside the riser main shaft.

Figure 6.2.5a. : Dutch roll folding method

Figure 6.2.5b. : Dutch rolled fire hose with cabinet (surface-mounted or recessed)

QPs are reminded to ensure that premise owners are aware of the manufacturer's recommendation for maintenance of the standby hoses provided on site.

Figure 6.2.8a.(3)(b)

The staircase serving the upper storey living quarters shall be compartmented from the shop area by minimum 1-hr fire-rated enclosures. The communicating side access door between the staircase and shop area at 1^st storey level shall be minimum ½-hr fire-rated and fitted with self-closer. This door shall always be kept in the closed position to prevent smoke and fire from spreading to the living quarters if there is a fire in the shop area.

Small buildings refer to detached and standalone buildings, such as guardhouse, pump house, bin centre, electrical substation. These would not be required to be provided with hydraulic hose reel. However, suitable type of fire extinguisher should be provided instead. For other types of small building, QPs should consult the SCDF before making building plan submission.

( No illustration )

1. The reel or drum should be of adequate size to wind up the 30m length hose.

2. The length of the hose should not exceed 30m. The main reasons are:

(a) an occupant using the hose reel to fight an incipient fire need not traverse more than 30m. Consideration must be given that the occupant needs to retrace his path to a safe exit if the incipient fire could not be put out. Thus, the aggregate travel distance to and from the incipient fire should not be excessive;

(b) longer than 30m hose would require a bigger reel which would create some difficulties in running out the hose and that jamming of tubing could occur when in use.

3. An operating instruction notice plate should be provided next to the stop valve. The hose reel operating instructions shall be:

“Turn on the inlet valve before running out the hose”

4. All hose reels should be tested at least once a year. The test is to ensure that they are maintained in working order and able produce a jet of water with a minimum of 6m throw.

5. Hose reels located in recesses or cabinets shall bear the appropriate sign in accordance with SS 508 

6. Hose reels are now required to be type tested by a recognised testing laboratory to meet the standard of EN 671 – 1 or equivalent and are subject to the Productivity & Standards Board Inspection Scheme.

Figure 6.2.8c.

EXTRACTS FROM SS 575

1. Minimum requirements

(a) As a minimum, the water supply to hose reels shall be such that when the two topmost hose reels with the least hydraulic head in a building are operating simultaneously, each will provide a jet of at least 6m in length at a flow rate of at least 0.4 L/s. For example, when a 30m length of hose reel tubing (Type A of BS 3169) is in use with a 6.5mm nozzle, a minimum running pressure of 1.5 bar will be required at the entry to each reel. Similarly, for a 4.5mm nozzle, a minimum running pressure of 4 bars will be required.

(b) Pipework shall not be less than 50mm nominal bore and feeds to individual hose reels shall be at least 25mm nominal bore.

2. Hose reel pump

(a) Where the water pressure in hose reel main needs to be boosted, the provision of an electrically driven pump is usually a convenient method. A duplicate standby pump shall also be provided.

(b) Both motors and pumps shall be sited in positions where they are protected against tampering and physical and fire damage and the electrical supply to them shall be by an exclusive circuit with the cables following a route of negligible fire risk or be provided with adequate protection.

(c) The hose reel pumps system shall come into operation automatically with a drop in pressure or a flow of water. Both pumps shall be automatically primed at all times.

(d) All pumps shall also be capable of being started or stopped manually. The standby pump shall be so arranged that it will operate automatically on failure of the duty pump. Where more than one source of electrical supply is available, the duty and standby pump shall be connected to the different sources.

(e) Connection for boosted supplies - pumps shall be fed from a suction tank or inter-connected tanks having a minimum capacity of 1100 L. The tanks shall be automatically supplied from a town main or a reliable source, controlled by a ball valve of minimum diameter 50mm.

(f) Use of domestic water tank - tanks supplying water for domestic purposes shall not be used as suctions for hose reel installations unless arrangements have been made for domestic supplies to be drawn off in such a manner that the requisite reserve of water for the hose reel installation is always preserved.

3. Connection for boosted supplies

Pumps shall be fed from a suction tank or inter-connected tanks having a min. capacity of 1100 L. The tank(s) shall be automatically supplied from a town main or a reliable source, controlled by a ball valve of minimum diameter 50mm.

4. Use of Domestic Water Tanks

Tanks supplying water for domestic purposes shall not be used as suctions for hose reel installations unless arrangements have been made for domestic supplies to be drawn off in such a manner that the requisite reserve of water for the hose reel installation is always preserved. There shall not be any risk of contamination of water due to stagnation in the tank. The design of such arrangement is subject to PUB’s approval.

Footnote: Hose reel and sprinkler systems can share the same water tank under the conditions stipulated in SS CP 52.

Not Acceptable

Figure 6.2.8d.(1) - 1

The distribution of hydraulic hose reels as shown above is not acceptable as there is a pocket of area that is beyond the coverage of the hose reels.

Not Acceptable

Figure 6.2.8d.(1) - 2

EXTRACT FROM SS 575

Distribution of hydraulic hose reel

1. Siting

a. Hose reels shall be sited in prominent and accessible positions adjacent to exits, preferably just outside protected corridors, lobbies or staircases on exit routes, but not inside staircases.

b. In planning the location of hose reels, consideration should be given to the following points:

(1) Access to hose reels should not be obstructed by the parking, loading and unloading of vehicles or by the location of furniture, equipment or other material.

(2) Protection of hose reels from mechanical damage and unauthorised use.

(3) The location of internal walls, partitions, doorways, storage racking, stored heights of goods and other obstructions, which could restrict normal hose coverage through the building.

2. Installation of hose reels

References shall be made to SS 575 for details on installation of the hose reel.

( No illustration )

1. Pipework for hose reel system shall not be less than 50mm nominal bore and feeds to individual hose reels shall be at least 25mm nominal bore.

2. Copper or stainless steel pipes can be incorporated in the pipe works supplying water to the hose reels.

The above sub-clause allows the flexibility of using alternative material for the water supply pipe of the hose reel system.