BSI PD 7974-6:2019
$215.11
Application of fire safety engineering principles to the design of buildings – Human factors. Life safety strategies. Occupant evacuation, behaviour and condition (Sub-system 6)
| Published By | Publication Date | Number of Pages |
| BSI | 2019 | 116 |
This Published Document is intended to provide guidance to designers, regulators and fire safety professionals on the engineering methods available for the evaluation of life safety aspects of a fire safety engineering design in relation to escape and tenability strategies.
The objective of the fire safety engineering strategy is to ensure exposure to the effects of fire does not impede the safe escape of occupants or cause exposure to conditions leading to adverse health effects.
Guidance is presented regarding the evaluation and management of occupant behaviour during a fire emergency and for the evaluation of occupant condition related to exposure to fire effluent and heat.
This Published Document addresses the parameters that underlie the basic principles of designing for life safety and provides guidance on the processes, assessments and calculations necessary to determine the location and condition of the occupants of the building, with respect to time. This is achieved using the information presented on the evaluation, quantification and management of occupant behaviour, particularly escape behaviour, during a fire emergency.
This Published Document also provides a framework for reviewing the suitability of an engineering method for assessing the life safety potential of a building for its occupants.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 5 | Foreword |
| 7 | Introduction |
| 9 | 1 Scope |
| 10 | 2 Normative references 3 Terms, definitions, symbols and abbreviations |
| 15 | 4 Principles |
| 17 | Figure 1 — Simplified schematic of processes involved in escape time compared to available safe escape time (ASET) |
| 22 | 5 Design behavioural scenarios for quantification of RSET pre-travel and travel times |
| 23 | Table 1 — Design behavioural scenarios and occupancy types |
| 26 | 6 Estimation of pre-travel times based on design behavioural scenario |
| 27 | 7 Estimation of travel times |
| 29 | 8 Interactions between pre-travel time, walking time and exit flow time for evacuation time calculations |
| 30 | 9 Calculation of escape and evacuation times for single enclosures and for multi‑storey or multi-enclosure buildings |
| 33 | 10 Occupant condition |
| 37 | Table 2 — Radiant heat exposure dose limits for different endpoints |
| 40 | 11 Application of computer evacuation models to calculation of escape times |
| 43 | 12 Summary |
| 46 | Annex A Guidance on the evaluation of detection and warning times |
| 50 | Annex B Pre-travel behaviours and determinants |
| 53 | Annex C Detailed information required for ASET and RSET calculations |
| 56 | Annex D Features of design behavioural scenario categories for derivation of RSET variables |
| 60 | Annex E Pre-travel time distribution data and derivations |
| 62 | Figure E.1 — Representation of pre-travel time distributions and effects of different levels of fire safety management Figure E.2 — Some examples of measured pre-travel time |
| 64 | Table E.1 — Pre-travel times derived from actual fires and evacuation exercises reported in the referenced literature (in minutes) |
| 67 | Table E.2 — Suggested pre-travel times for different design behavioural scenario categories (minutes) |
| 71 | Annex F Guidance on travel distances and occupant densities |
| 72 | Figure F.1 — Generic retail enclosure Figure F.2 — Distributions of travel distances to nearest exit for a randomly dispersed population in the enclosure shown in Figure F.1 with and without obstructions |
| 73 | Annex G Guidance on travel speeds and flow rates |
| 75 | Figure G.1 — Effective width for a stair (see Pauls, 2003 [17]) Table G.1 — Boundary layer widths |
| 77 | Table G.2 — Constants for Equation (G.1) (effects of density on travel speed), maximum unimpeded travel speeds (m/s) and flow rates (persons/s/m of effective width) for horizontal and stair travel Table G.3 — Summary of maximum flow rates |
| 78 | Table G.4 — Maximum flow capacities (from ADB [1]) |
| 82 | Table G.5 — Travel speeds reported in the referenced literature — Where density was reportedly not a factor |
| 84 | Table G.6 — Travel speeds reported in the referenced literature — Where density was a factor |
| 85 | Annex H Example of interactions calculations |
| 86 | Figure H.1 — Distribution of pre-travel, walking and presentation times of randomly dispersed occupants of retail enclosure shown in Figure F.1 using Sprucefield pre‑travel time distribution |
| 87 | Figure H.2 — Phases of evacuation times for different populations in a square prescriptively designed retail enclosure with an area of 18 000 m2 calculated using GridFlow with the Sprucefield pre-travel time distribution |
| 88 | Table H.1 — 99th percentile evacuation time predictions using three methods |
| 89 | Annex I Effects of smoke on walking speed and proposed tenability endpoints for smoke, toxic gases and heat |
| 90 | Figure I.1 — Walking speeds in non-irritant and irritant smoke Table I.1 — Smoke tenability limits |
| 92 | Table I.2 — Values for VE and DCO for input to Equations (I.4) and (I.6) depending on activity level |
| 93 | Table I.3 — Proposed design tenability limit exposure concentrations for asphyxiant gases expressed as carbon monoxide for 5 min and 30 min exposures Table I.4 — Tenability limits for radiative and convective heat |
| 94 | Table I.5 — Illustration of an ASET FED analysis for the first 6 min of a furniture fire based on a single armchair room burn |
| 95 | Figure I.2 — Plots of the FED analysis calculated in Table I.5 |
| 96 | Figure I.3 — Estimated radiant heat flux (kW/m2) to subject with walking time(s) for two flame sizes |
| 97 | Figure I.4 — FED for pain to exposed skin for subject walking past the flames in Figure I.2 Annex J Generic worked examples for a number of design behavioural scenarios |
| 99 | Table J.1 — Escape time calculation for low occupant density level 1 office |
| 100 | Table J.2 — Escape time calculation for high occupant density level 1 office Table J.3 — Escape time calculation for low occupant density level 2 office Table J.4 — Escape time calculation for high occupant density level 2 office |
| 101 | Table J.5 — Escape time calculation for low occupant density level 3 office |
| 103 | Table J.6 — Escape time calculation for high occupant density level 1 retail |
| 104 | Table J.7 — Escape time calculation for high occupant density level 2 retail Table J.8 — Escape time calculation for level 3 retail |
| 109 | Bibliography |
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