Main author

Business Sprinkler Alliance Institute / association Website
Last edited 09 Nov 2017

Case study B for offices to show where automatic sprinklers have the greatest impact

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.

See also: Case study A for offices to show where automatic sprinklers have the greatest impact.


This example features a four-storey office building located in Manchester with 1,600m2 GIA and fully-glazed facades. The separation distances around the building are:

  • Offices 20x20 m2.
  • 4 storeys – c. 16m.
  • Separation distances are; Northern side 11m, Eastern side 20m, Southern side 12m, Western side 15m.
  • Glazed façade.
  • Occupancy capacity of the building.
  • 2 staircases.
Spinkler case study 2 image 3.jpg
Spinkler case study 2 image 1.jpg
Spinkler case study 2 image 2.jpg

Firstly, the impacts of incorporating an automatic sprinkler system on the fire protection measures are demonstrated in Table 6-4. Secondly, cost analysis of the impacts is conducted in Table 6-5.

[Table 6-4 Impact of sprinklers on the required fire protection measures for Building B]

BUILDING B Without Sprinklers With Sprinklers
Fire-rated façade area required Northern side (12.5%) = 40 m2

Southern side (0%) = 0 m2

Eastern side (0%) = 0 m2

Western side (0%) = 0 m2

Northern side (0%) = 0 m2

Southern side (0%) = 0 m2

Eastern side (0%) = 0 m2

Western side (0%) = 0 m2

Stairs minimum width 1000 mm

Stairs area 24m2 per floor

1000 mm

Stairs area 24m2 per floor

Structural fire protection rating 60 minutes 30 minutes
Dry risers 1 1


[Table 6-5 Cost analysis of incorporating sprinklers in Building B]


BUILDING B

Without Sprinklers

With Sprinklers

Sprinklers installation cost

£0

£97,600

Façade cost14

Non FR façade= 1,240m2 x £600/m2 = £744,000

60min-FR façade= 40m2 x £1,700/m2 = £68,000

Total = £812,000

Non FR façade= 1,280m2 x £600/m2 = £768,000

Total = £768,000

Structural fire protection cost

60min-FR = 1,600m2 x £21.57/m2

= £34,512

30min-FR = 1,600m2 x £12.38/m2

= £19,808

Rental yields derived from changes to net internal area

0 m2

0 m2

Dry risers costs

1 x £1,500/landing x 4 floors =

£6,000

1 x £1,500/landing x 4 floors =

£6,000

Total costs

£852,512

£891,408

Total cost impact of sprinklers

Capital cost impact = £38,896 added to the project cost plan by including sprinklers


Verdict: Installing automatic sprinklers in Building B is shown to add cost to the project and would not be recommended when reviewed against the impacts (cost, aesthetics etc.) reviewed herein. Unless there is another requirement requiring their inclusion (business continuity, property protection).

Read more: The impact of automatic sprinklers on building design.

Reference [14] Glazed fire rated façade assumed required for aesthetic reasons by the client.

--Business Sprinkler Alliance

[edit] Find out more

[edit] Related articles on Designing Buildings Wiki