C.1 General

NOTE 1 Recommendations for the design of atrium buildings are given in Annex B.

This annex gives a range of design solutions for atrium buildings with occupancy characteristics A, B and Ciii.

NOTE 2 Atrium buildings with occupancy characteristics Ci and Cii are covered in BS 9991.

a) Annex Decision Tree Process:

· Guides users through questions to determine appropriate design solutions.

b) Components of Each Decision Tree:

· Fundamental question.

· Series of suggested solutions.

c) Common Pattern in Decision Trees:

· Evaluate the evacuation procedure.

· Determine the type of fire alarm/automatic detection system.

· Decide on separation between the atrium and other areas.

· Choose the type of smoke control system.

· Consider the use of the atrium base.

· Provide automatic suppression systems.

d) User Instructions:

· Follow the decision tree strictly.

· Do not select solutions from unrelated branches.

C.2 Occupancy characteristics A

The decision processes for occupancy characteristic A (occupants who are awake and familiar with the building) are illustrated in Figure C.1 to Figure C.3.

The corresponding exemplars are illustrated in Figure C.4 to Figure C.7.

C.4 Occupancy characteristic Ciii

The decision processes for occupancy characteristic Ciii (short term occupancy with occupants who are likely to be asleep) are illustrated in Figure C.1,

Figure C.18 and Figure C.19. The corresponding exemplars are illustrated in Figure C.20 to Figure C.22.

Figure C.1 Occupancy characteristic and atrium height- Initial decisions

Figure C.2 Occupancy characteristic A – Atrium height less than 30 m

Figure C.3 Occupancy characteristic A – Atrium height greater than 30 m

Figure C.4 Exemplar 1- Occupancy characteristic A- Atrium height less than 30 m simultaneous evacuation

Figure C.5 Exemplar 2- Occupancy characteristic A- Atrium height less than 30 m simultaneous evacuation

Figure C.6 Exemplar 2- Occupancy characteristic A- Atrium height less than 30 m simultaneous evacuation

Figure C.7 Exemplar 2- Occupancy characteristic A- Atrium height less than 30 m phased evacuation

Figure C.8 Occupancy characteristic B- Atrium height less than 18m

Figure C.9 Occupancy characteristic B- Atrium height less than 18m not open to floor areas

Figure C.10 Occupancy characteristic B- Atrium height greater than 18m

Figure C.11 Occupancy characteristic B- Atrium height greater than 18m not open to floor areas

Figure C.12 Occupancy characteristic B- Atrium height less than 18m open to floor areas

Figure C.13 Exemplar 6- Occupancy characteristic B- Atrium height less than 18m not open to floor areas, not fire- resisting

Figure C.14 Exemplar 7- Occupancy characteristic B- Atrium height less than 18m not open to floor areas, minimum 30 min fire- resisting

Figure C.15 Exemplar 8- Occupancy characteristic B- Atrium height greater than 18m open to floor areas

Figure C.16 Exemplar 9- Occupancy characteristic B- Enclosed atrium of any height greater than 18m, not fire- resisting

Figure C.17 Exemplar 10- Occupancy characteristic B- Enclosed atrium of any height greater than 18m, fire- resisting

Figure C.18 Occupancy characteristic Ciii- Atrium any height

Figure C.19 Occupancy characteristic Ciii- Atrium any height escape through the atrium

Figure C.20 Exemplar 11- Occupancy characteristic Ciii- Atrium any height escape not through atrium

Figure C.21 Exemplar 12- Occupancy characteristic Ciii- Atrium any height escape through atrium smoke- separated

Figure C.22 Exemplar 13- Occupancy characteristic Ciii - Atrium any escape through atrium not smoke- separated

Annex C (informative)Design solutions and exemplars for atria