Sprinkler 001

Fundamental Approach ToSprinkler System Design

Presented byLam Chi Shing

16 April 2004

Introduction

• Reference• FS Notes• Design Issues• Break• Worked Examples• Q&A

Reference

• Codes of Practice for Minimum Fire Service Installations and Equipment and Inspection, Testing and Maintenance of Installations and Equipment

• FSD Circular letters• British Standard BS 5306 Part 2: 1990

(Rules for Automatic Sprinkler Installations, The Loss Prevention Council – LPC)

Reference con’t

• LPC Technical Bulletins (e.g. TB13, High Rise Sprinkler System)

History

• Before 1 April 1995 – Rules of the FOC for Automatic Sprinkler Installation 29th

Edition• After 1 April 1995 – LPC Rules

FS Notes Submission via GBP

• Areas to be protected by sprinkler• Hazard classification• Water tank size and location• Inlet location• Control room location• Direct telephone line provision

Example of FS Notes

TWO INDEPENDENT AUTOMATIC SPRINKLER INSTALLATIONS SHALL BE PROVIDED IN ACCORDANCE WITH THE CURRENT LPC RULES TO PROTECT SHOPPING ARCADE INCLUDING PUBLIC CARPARK AND RESIDENTIAL CARPARK/CLUB HOUSE RESPECTIVELY. NO SPRINKLER SYSTEM WILL BE PROVIDED FOR TRANSFORMER ROOMS, SWITCH ROOMS, EMERGENCY GENERATOR ROOMS, TELECOMMUNICATION AND BOARDCASTING EQUIPMENT ROOM, FUEL TANK ROOM, ALL CANOPIES, M&E PLANT ROOMS AND DUCTS.

Example of FS Notes (con’t)

THE HAZARD CLASSIFICATION OF SPRINKLER SYSTEM SHALL BE AS FOLLOWS :

CARPARK : OHIII

SHOPPING ARCADE : OHIII

CLUB : OHII


AS ADVISED BY THE WATER WORKS OFFICE, THE WATER MAIN IS OF SINGLE-END FED. HENCE,

AN INDEPENDENT SPRINKLER SYSTEM CONSISTS OF 107m3 SPRINKLER WATER TANK AND SPRINKLER PUMPS LOCATED AT L1 SHALL BE PROVIDED FOR SHOPPING ARCADE INCLUDING PUBLIC CARPARK.


THE SPRINKLER INSTALLATION WILL BE SO DESIGNED THAT ACTUATION OF ANY ONE SPRINKLER HEAD WILL GIVE INDICATION, THROUGH FLOW SWITCHES, TO THE SPRINKLER ANNUNCIATION PANEL AND THE FIRE ALARM SIGNAL WILL BE LINKED TO THE FIRE SERVICES COMMUNICATION CENTRE BY A DIRECT LINK.


ALL SPRINKLER HEADS INSTALLED INSIDE CLUB HOUSE AND RESTAURANT AREA TO BE FAST RESPONSE TYPE.

79°C SPRINKLER HEADS WILL BE PROVIDED UNDER SKYLIGHT AND 93°C SPRINKLER HEADS WILL BE PROVIDED ALONG KITCHEN EXHAUST HOODS.


SPRINKLER SYSTEM AT STAIRCASE SHALL BE EXTENDED TWO MORE FLOORS ABOVE PODIUM WITH FAST RESPONSE TYPE SPRINKLER HEADS.

SPRINKLER INLETS SHALL BE PROVIDED ON GROUND FLOOR AT POSITIONS, WHERE CAN BE REACHED BY FIRE APPLIANCE, AS INDICATED ON PLANS. SPRINKLER INLETS FOR COMMERCIAL SYSTEM AND RESIDENTIAL SYSTEM SHALL BE INTERCONNECTED.

Hazard Classification

• Light – Non Industrial area less than 126 m2

• Ordinary – Group I, II, III & IIIs (Table 3 on LPC)• To allow flexibility in change of use, warehouse

and high rise building should be classified at least OHIII

• High – Processing & High pile storage (Table 1, 2 & 4 on LPC)

• In HK, some buildings with total floor area less than 230 m2 need not be provided with sprinkler

Table 3

Table 1

Table 2

Table 4

Type of Sprinkler Installation

• Installation – Part of sprinkler system comprising a set of installation main control valves, the associated downstream pipes and sprinklers.

• Wet pipe• Alternate (wet and dry)• Dry pipe• Pre-action• Recycling


• Wet pipe – An installation in which the pipework is always charged with water

• Alternate – An installation in which the pipework is selectively charged with either water or air according to the ambient temperature conditions

• Dry pipe – An installation in which the pipework is charged with air under pressure


• Pre-action – One of two types of dry, or alternate in dry modes, installation in which the alarm valve can be opened by an independent fire detection system in the protected area

• Recycling – A pre-action installation in which the alarm valve can be opened and closed repeatedly by a heat detection system

Design

• Since the major projects are generally classified as Ordinary Hazard and for the purpose of life safety, they will be used as reference thru out this talk

• Pipe sizing – fully hydraulically calculated (not recommended) or pre-calculated (commonly used)

System Size

• 200 per zone and unlimited per installation (For Life Safety)

System Size

• 500 per installation if not divided into zones for Light Hazard

• In single-storey buildings, or unheated service areas and car parks near or below ground level in multi-storey buildings, ordinary and / or high hazard inclusive of any light-hazard sprinklers on the same installation main control valve set - 1000 per installation if not divided into zones for Ordinary Hazard

System Size

• In Multi-storey buildings, and for high-rise systems, excluding unheated service areas and carparks near or below ground level – 500 per zone, or an installation is not divided into zones, 1000 per installation

• High hazard – 1000 per installation

Control Valve

• Zoned Installation1. One alarm valve set with by-pass stop valve or2. Duplicated alarm valve set

• Un-zoned InstallationOne alarm valve set

Zone Valve

• Also known as subsidiary valve• Required for each zone• With label to identify the area of protection

Notes: All stop valves including subsidiary valve and main valves shall be completed with electric switch to indicate the correct mode in annunciation panel

Water Supply

• Gravity Tank• Automatic suction pump and tank

Notes: water tank other than concrete shall be LPC approval type

Water Supply

Gravity tanks• For high rise systems, 2V or,• For low rise system either V/f is less

than 0.36 the appropriate design capacity V as specified in table 20 or V/f is not less than 0.36 (2V –0.36f should be used)

Water Tank Capacity

• Not depended on inflow (per-calculated installation) – Table 22

• Depended on inflow – Table 25• Refilling rate not less than 75L/min• In HK, where sprinkler alarm is connected to Fire

Services Communication Centre via direct telephone line, tank capacity can be reduced to 2/3 of the full holding capacity

• Effective capacity – Fig 23 & Table 32

Table 22

Table 25

Table 32

Figure 23

Pump Pressure and Flow Requirements

• Refer to Table 28

Table 28

Pump Suction

• Suction pipe size – 150mm diameter for OH I & II, 200mm diameter for OH III

• 3.43Q ½ for high hazard• Equivalent pipe length not more than 30m

for pre-calculated pipework• Foot valve shall be fitted to the suction

pipe where not less than one-sixth of the effective stored water capacity is contained

Pump Suction

• Separate priming tank shall be provided under suction lift condition (more than 2 m depth of water or one-third of the effective capacity is contained between the pump centre line and the low water level)

Max Pressure Losses between Design Point and Control Valve (Ordinary Hazard)

• Based on flow rate of 1000L/min• Max pressure loss is 500mb (0.5bar)

Pressure Loss Calculation

• Generally used Table 36 & 37• P = k x L x Q1.85

Where P is total fiction lossk is k factor of pipeL is total equivalent pipe lengthQ is design flow rate (1000L/min in OH hazard)

• For pre-calculated installation, each fitting is counted as 3m

Pressure Loss per Unit Length

• Table 59Dia mbar/m65 3580 16100 4.4150 0.65200 0.16

Sizing of Range and Distribution Pipe

• Table 57 & 58• Basically

Dia No of Spr32 340 650 965 18

• Using 25mm shall be minimized because the allowable equivalent length is 5.2m (1m for 90o

elbow)

Table 57, 58

Sprinkler Head Coverage and Spacing

• Table 70, 71 and Fig 38, 39• For non-sidewall sprinkler

Max area coverage = 12m2

Max distance between sprinklers 4m (standard)4.6m (staggered)

Max distance to open end : 1.5mMin distance between sprinklers : 2m

Table 70

Table 71

Sprinkler Head Coverage and Spacing

• For sidewallMax area coverage = 9m2

Max distance between sprinklers : 3.4m• Table 77 & Fig 47 – beam rules of sprinkler

layout• Clear space below sprinkler is 0.5m in

general• Distance below ceiling slab is 75mm to

450mm

Table 77 and Fig. 47

When Double Layer Required

When space of false ceiling void exceeded 800mm, orWhen combustible materials were installed inside ceiling void.

Sprinkler Selection

Temperature rating• Higher than ambient 300C• Normal 68 / 740C• Glazed roof 79 - 1000C

Fast Response Sprinkler

In HK, FSD requires fast response sprinkler to be used

• Inside staircase between commercial floor and residential floor

• Inside basement• Concealed sprinkler

Worked Example

Current Requirements During FS Inspection

If water fed by gravity tank, actual flow test for high zone remote 16/18 heads are required to ensure the storage capacity can last for half an hour.

Current Requirements During FS Inspection (con’t)

Intermediate booster pumps are required for high rise building. Test will be carried out at the remote point to see whether adequate flow and pressure can be maintained.


Power cable for sprinkler pumps shall be fire rated, otherwise fire rated enclosure solely used by that cables shall be provided.


All equipment used shall be LPC approved. Updated LPC certificate shall be presented during FSD inspection.


Low layer sprinkler heads shall be provided at the centre of obstruction if required. Effective for GBP submitted after 1 Feb 2003.


• Equipment pressure rating shall match with the system pressure (refer to 21.2.6 of LPC rule, flexible pipe and swivel joints shall be with standing a test pressure of four times the maximum working pressure or 40 bars, whichever is greater


Nominal rating will be tested . The pressure rating shall be maintain +5% as required.


Improvised sprinkler- FSD- WSD- BD


Cold Store Design- Dry pipe sprinkler- Pre-action sprinkler (shall be accepted by

FSD)


No of inlet required

Determine by flow vs pressure loss


Pressure switch shall be fail safe (ie NC).


LMCP shall be provided with dual lamps.


Where sprinkler heads installed under fire rated ceiling, sprinkler cover plates cannot be used. It is considered as no fire rated.


Spray patter sprinklers shall not be used as follows:

• In high hazard, high piled storage application

• As roof or ceiling sprinklers in ordinary or high hazard application is exposed structural steelwork or the roof or ceiling or its support structure is of combustible material

• END

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Sprinkler 001