The Purple Guide to Health, Safety and Welfare at Music and Other Events — Crowd Management[1]
Summary
Defines crowd dynamics, citing Keith Still, as the study of how and where crowds form and move above the critical density of more than one person per square metre (§54). Describes the DIM-ICE model — Design, Information and Management across Ingress, Circulation and Egress — in use over 30 years, evolved from research into crowd incidents, allowing risks to be seen through the lens of past failures (§56–57). Introduces Zone Ex and Publicly Accessible Locations: the arrival and departure territory outside the perimeter, where organisers must liaise and plan but hold no legal powers and no liability (§62–63). States that event capacity includes staff, contractors, guests, performers, volunteers and all those with a statutory duty to be on site (§49). Sets out the full show stop procedure (§149–162): definition as an immediate threat to life; internal triggers including crowd collapse and excessive crowd density; a named list of personnel who may initiate; advance agreement with performer management; a designated audience communicator with a competent alternative because some performers cannot address a crowd in an emergency; performers to remain on stage where safe because they keep the audience calm; and restart via consultation, formalised by a Return of Authority form where primacy was transferred. Requires trained crowd spotters in elevated positions at front of stage operating to a pre-agreed protocol, specifically where an event may need to be stopped mid-performance (§87). Notes ingress is a steady flow over a longer time while egress is a condensed flow over a shorter time (§128). Holds that young children, particularly under-fives, may not be appropriate at events by reason of crowd scale or density (§108), requires a Vulnerable Persons Policy (§110) and Enhanced DBS clearance for staff working with children (§111).
So what
Section 54 is the threshold figure the library was missing, from the discipline's leading authority, with a citation — and it independently confirms that a campsite at roughly 0.1 persons/m² is not a crowd-dynamics problem at all. Section 49 exposes a methodological problem with the field's core metric: US patient presentation rates are expressed per 10,000 attendees where attendance means tickets, but the population at risk includes the workforce, which is present during build and break when the audience is not and carries a different risk profile. The denominator is wrong in the direction that inflates the rate. Section 150 lists who is in the show stop decision and the medical lead is not among them, despite two of the six internal triggers being crush conditions the medical team treats first — the same governance gap the SAG chapter shows, now with a second independent instance. The medical tent is an independent density sensor that front-of-stage spotters cannot be, because a cluster of syncope from one sector arrives at the tent rather than the barrier; a defined presentation threshold routed to event control would close that loop cheaply. Zone Ex names a doctrinal blind spot that several real mass-casualty crowd events occupy.