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Business Sprinkler Alliance Institute / association Website
Last edited 13 Oct 2017

The cost efficiency of different combinations of fire protection measures

This article was originally published as part of The impact of automatic sprinklers on building design, an independent report produced by WSP, sponsored by the Business Sprinkler Alliance (BSA), published in September 2017.

Contents

[edit] Introduction

This article provides background information on the pricing used within this document to determine the cost efficiency of different combinations of fire protection measures. It has been compiled based on our knowledge of building design with support provided by a qualified quantity surveyor to ensure a reasonable level of reliability in the figures quoted. The main references used here are Spon’s price books and the figures should be seen as indicative. Variations will occur for local reasons (e.g. central location means difficult access and parking) and, regional variations to building costs quoted here are estimated to be between +6% (in central London) and -10% (in Wales).

To enable comparison between different fire protection measures and the impact of different design features, costs are typically converted to a unit cost per m2 of floor area.

Further financial savings through reduced insurance premiums may also be realised although they are not considered further in this report.

[edit] Costs of water automatic sprinkler systems

An approximate estimate of installing automatic sprinkler systems to establish viability is given as follows:

Whilst the infrastructure cost (£60,000-£80,000) does vary depending on the building size, it only does so in a minor fashion due to fact that automatic sprinklers are designed to operate a fixed number of heads independent of floor area. Therefore as the building grows in size, the cost associated with the infrastructure does not vary significantly. This means that the cost efficiency of automatic sprinklers generally increases with building size.

The number of sprinkler heads required varies depending principally on the type of risk to be protected (i.e. category of building type) and layout. For most building types, automatic sprinklers are orientated on a 4m x 3m ceiling grid which gives 1 sprinkler head per 12m2 but as noted above, that is an ideal situation and further heads will be required to suit internal partitions and different building footprints. Therefore 15% has been added to the above figure to give a £/m2:

  • £180 per head;
  • 3m x 4m coverage from a single head;
  • 15% layout allowance.
  • Total = £17.25/m2 GIA [6] + Sprinkler infrastructure (£70,000)

Other factors may influence the area of coverage such as whether a building has deep ceiling voids which may need protection or sterile areas such as stairs and toilets that may not.

For a comparison the rates shown in Table 5-1 are “Shell and Corecosts for installing automatic sprinkler systems (including the water supply) for Offices with GIA between 3,000 – 15,000 m2 and hotels (2 to 5 stars). These rates highlight the variability in costs between building types.

[edit] Table 5-1: Generic pricing – sprinkler system installation

Building use Installed as part of building shell

Rate /m2

Installed as part of building fit-out

Rate /m2

Office – central London £16.37 £21.21
Office – regional (average) £14.73 £19.08
Warehouse ( fitted racking installed) £42.32 n/a
Hotels (2 – 5*) £20 – 30 n/a

To ensure these generic rates shown above (Table 5-1) are reasonable, specific cases of cost analyses provided by Spon’s price book (shown in Table 5-2) are reviewed;

  1. Installing a sprinkler system in the office building example shown in Table 5-2 costs £316k and averages to £16.37/m2 GIA. This rate is within the generic ranges quoted earlier (i.e. £17.25/m2 + £70k and £15-20/m2).
  2. In another example, the costs of providing automatic sprinkler system and dry risers to a 4* hotel were £596k and averaging to £36.12/m2. In order to compare this figure (£36.12/m2) with £20-30/m2 from Table 5-1 the cost of dry risers has to be discounted leaving the rate as £26.12/m2. This rate £26.12/m2 falls almost in the middle of the generic price range shown in Table 5-1 and confidence can be placed in the values presented.

These examples demonstrate that the actual cost of installing automatic sprinkler system for each building depends on many factors, however the rates quoted in Table 5-1 can be used as a guide for estimating costs based on GIA.

[edit] Table 5-2: Real examples of installing sprinkler system costs in different types of buildings

Case study

Total Sprinkler Cost

Cost / m2 GIA

Office building located in Central London, 15 floors, GIA = 19,300 m2

£316,000

£16.37/m2

4* Hotel, 200 bedrooms, located in Central London, 10 floors, GIA = 16,500 m2

(inc. dry risers) = £596,000

(inc. dry risers) =

£36.12/m2

Airport terminal building located in the South East, GIA= 25,000 m2

£790,000

£31.60/m2

Shopping mall located in the South East comprised;

Two storey retail area, GIA = 33,000 m2

£415,000

£12.57/m2

Covered car park, GIA = 13,000 m2

£270,000

£20.76/m2

Distribution centre (Warehouse), located in outer London, GIA = 75,000 m2 (inc. refrigerator area GIA=17,500m2)

(inc. racking protection)= £3,174,000

£42.32/m2

[edit] Costs of dry risers

The incorporation of automatic sprinklers into building design can be used to justify a reduction in the number of dry risers required in a building. All-in rates for approximate estimates of installing dry risers are as follows:

  • 100mm dry riser + 2-way breeching valve and box (65mm landing valve + padlock + leather strap + automatic air vent + drain valve) = £1,500 per landing

The number of risers required depends on the layout of the building, as the minimum requirement is reported as “reach” from the dry riser outlet to completely cover the floor plate.

Different estimates for costing the installation of dry risers per GIA for offices and hotels are also quoted in Spon’s (see table 5-3). If an automatic sprinkler system is installed, a reduction of the number of dry risers by up to 33% (based on the 33% increase in reach from 45m to 60m) is theoretically possible. This is tabulated below.

[edit] Table 5-3: Generic pricing – “Shell and Core” installation of dry risers

Building type Dry risers cost

£/m2 GIA

Potential savings

£/m2 GIA

Offices (3,000 – 15,000 m2) 3 – 5 1
Hotels 8 – 12 2-4

[edit] Costs of staircases

One of the impacts of incorporating automatic sprinkler systems on the capital cost is to use the increased fire protection offered to look at the possible removal of escape staircases. The cost associated with constructing a staircase in an office building in central London with 13 floors is estimated at £200k with an average of c. £15k per floor. Stairs may also require secondary fire protection measures such as fire-rated lobbies and smoke ventilation systems. An example of the latter is a stair pressurisation system for which a rate of £6/m2 GIA is applicable.

[edit] Costs of glazing

Prices for fitting different types of glazing internally for compartmentation purposes (inclusive of labour costs) are as follows:

The above prices are for glass that can be used within the building interior, i.e. protected corridors, atriums etc. For external glazing, a self-conducted market survey yielded the following for rates for fire-rated façade systems. These have additions such as fire treatment on the glass itself, increased robustness of the frame and intumescent sealing of the edges:

  • Non-FR glazed façade (£500/m2 – £700/m2)
  • 30-min FR glazed façade (£900/m2 – £1,000/m2)
  • 60-min FR glazed façade (£1,600/m2 – £1,800/m2)
  • 90-min FR glazed façade (£2,000/m2 – £2,400/m2)
  • 120-min FR glazed façade (£3,000/m2 – £3,400/m2)

[edit] Costs of structural fire protection

Prices for providing fire protection to steel structures expressed as cost per m2 rate of surface area of the steel:

Spray

  • 60min-FR range (£8.55/m2 – £12.30/m2)
  • 90min-FR range (£14.30/m2 – £20.00/m2)

Intumescent coating

  • 30min-FR range (£8.70/m2 – £11.10/m2)
  • 60min-FR range (£11/m2 – £23.50/m2)
  • 90min-FR range (£32/m2 – £39/m2)
  • 120min-FR range (£48/m2 – £59/m2)

FR boarding

  • 30min-FR range (£29/m2 – £45.50/m2)
  • 60min-FR range (£41/m2 – £62/m2)

This can be converted (approximately) to a more practical rate per floor area. Typical steel structure in buildings is 50 kg/m2 GIA (gross internal floor area). Typical steel mass per surface area in a structural element is 40 kg/m2. Therefore a price in (£ per painted surface area) can be converted to the conventional cost unit of £/m2 GIA;

£/m2 GIA = (£/m2 surface area) x (50 kg/m2 GIA) ÷ (40 kg/m2 surface area)

Spray

  • 60min-FR range (£10.69/m2 GIA – £15.38/m2 GIA)
  • 90min-FR range (£17.88/m2 GIA – £25.00/m2 GIA)

Intumescent coating

  • 30min-FR range (£10.88/m2 GIA – £13.88/m2 GIA)
  • 60min-FR range (£13.75/m2 GIA – £29.38/m2 GIA)
  • 90min-FR range (£40/m2 GIA – £48.75/m2 GIA)
  • 120min-FR range (£60/m2 GIA – £73.75/m2 GIA)

FR boarding

  • 30min-FR range (£36.25/m2 GIA – £56.88/m2 GIA)
  • 60min-FR range (£51.25/m2 GIA – £77.5/m2 GIA)

[edit] Summary of capital costs

Total cost of sprinkler system installation (ordinary hazard classification) = £70k + (GIA x £17.25/m2)
Total cost of dry risers = £1,500 x number of floors x number of risers
Cost of a staircase = £15k x number of floors x number of staircases

Total cost of façade glazing per façade area:

  • Non-FR glazed façade (£500/m2 – £700/m2)
  • 30-min FR glazed façade (£900/m2 – £1,000/m2)
  • 60-min FR glazed façade (£1,600/m2 – £1,800/m2)
  • 90-min FR glazed façade (£2,000/m2 – £2,400/m2)
  • 120-min FR glazed façade (£3,000/m2 – £3,400/m2)

[edit] Table 5-4 Cost of sprinklers vs. potential savings

Sprinkler system cost (OH) = £70k + (GIA x £17.25)

Potential savings on

Dry risers

= £1-3/m2 GIA

Staircases

= £15k/floor/staircase removed

Façade FR glazing system

= up to £2,700/m2 x wall area

Structure FP

= £10.88-77.50/m2 GIA

[edit] Lifecycle costs

The values given above are those associated with capital costs. The lifecycle cost associated with each measure varies although it should be factored in when considering the lifespan of a building. For this report, lifecycle costs are not explicitly considered because they will be project-specific and complex to estimate.

[edit] References

[6] Gross Internal Area that includes; all areas occupied by internal walls and open-sided covered areas, but excludes; open balconies, open fire escapes, and open-sided covered ways. It is the total floor area of all storeys, not the building footprint area.

Find out more at: The impact of automatic sprinklers on building design.

--Business Sprinkler Alliance

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