07Building a city in a field

The short version: A big greenfield festival is a small town built from nothing and taken apart again: stages, power, water, toilets, phone masts, fences and roads, assembled over weeks to months. In the UK the reference manual for doing it safely is the Purple Guide, published by the Events Industry Forum; it is guidance, not law. The law sits elsewhere - licensing acts, fire rules, health and safety duties - and in the US it is mostly local, city by city and county by county. Boston Calling shows how a city festival changes its layout from year to year.

How long does it take to build a festival?

Longer than the festival lasts, by a wide margin. At Glastonbury 2019, construction of a single area - Block9's IICON stage - had begun nearly three months before Vice's June 2019 report, published just ahead of the festival. Its components arrived on site at the start of June for a late-June festival, more than 1,000 people worked on that one project, and it used about 6.5 km (4 miles) of scaffolding, according to Vice's reporting.¹¹⁷

The phone network arrives early too. For the same 2019 festival, the carrier EE drove six temporary mobile sites onto the farm in mid-May, with 20 engineers working on them. Vice reported the festival's data use on EE's network had grown from 1 TB in 2013 to 54 TB in 2017, with over 80 TB expected for 2019.¹¹⁷

Multiply that by every stage, bar, campsite and service road, and the build becomes the longest phase of the festival year. The load-out runs the same process in reverse, usually faster, because nobody is building anything to last.

The main stage goes up early as well. For Glastonbury 2022 (June 22-26), Emily Eavis posted a photo of the Pyramid Stage getting its covering at the end of March, and by April 10 ITV reported it "almost fully dressed" - roughly 10 to 12 weeks before the gates opened.¹¹⁸

What is the Purple Guide?

The Purple Guide is the UK's main good-practice manual for outdoor music and other events. The Health and Safety Executive (HSE), the UK government's workplace safety regulator, first published it; "its publication was taken over by the Events Industry Forum in 2012."¹¹⁹ The Events Industry Forum is an industry body, not a government department.¹²⁰

The Guide says it "is not designed to be prescriptive," and that its job is to "highlight legal responsibilities and non-legislative good practice."¹¹⁹ Most chapters are behind a subscription ("Login or subscribe to read more"), and the Forum says subscription income, after admin costs, goes back to the industry as grants.¹²⁰¹¹⁹

Flintshire County Council in Wales describes the "New Purple Guide" as the replacement for the original HSE guide, known as HSG195. The council says plainly that the Guide "is not the law," carries a subscription charge, and covers the Licensing Act 2003, the Civil Contingencies Act 2004 and the Regulatory Reform (Fire Safety) Order 2005.¹²¹

In practice, "not the law" does not mean optional. Councils, licensing officers and safety advisers use the Guide as the shared reference point, so an event plan that ignores it has some explaining to do.

The HSE edition traveled. Roskilde Festival in Denmark says that after its 2000 disaster it helped promote "The Event Safety Guide" (the HSE guide) and was among the first to implement it.¹²²

The HSE lineage goes back to 1993, when it published the Guide to health, safety and welfare at pop concerts and similar events. The second edition, retitled The Event Safety Guide (HSG195), followed in 1999.¹²³ As of November 2026, a single-user Purple Guide subscription costs £25 plus VAT a year, with multi-user plans also offered.¹²⁴

How many toilets does a festival need?

The UK starting point, quoted in the free preview of the Purple Guide's sanitation chapter for a typical local event, is "one female toilet per 100 attendees and one male toilet per 500 attendees plus one urinal per 150." The Guide adds that "more female toilets are needed than male toilets."¹²⁰

Pembrokeshire County Council publishes the ratios split by how long the gates are open, and refers organizers to British Standard BS 6465 Part 1 (2006) and the Purple Guide:¹²⁵

These are starting points. Councils adjust for the crowd mix, alcohol, camping and event length, which is why a camping weekend needs more than a one-day city show of the same size.

At scale the numbers get large. Vice's 2019 profile of Glastonbury's toilet contractor, Natural Event, reported about 13 build crew rising to about 100 staff once the gates open, and an estimated 1.3 million door openings over the festival. The same article gives the contractor's toilet count as both 1,111 and "11,000," so the exact fleet size is unclear from that source.¹¹⁷

In the US, the numbers are set locally, usually by county health departments. Salt Lake County in Utah, for example, uses a mass-gathering permit table based on peak crowd size and hours on site, requires 40% more toilets when alcohol is served, and asks for at least one hand-wash station per 10 toilets (application form loaded November 2026).¹²⁶

Where does a festival's drinking water come from?

The Purple Guide states: "It is essential to make sure that drinking water (aka potable water) is available on site," and singles out hot weather and sites without mains water.¹²⁷ On a farm that means bowsers, tanks and temporary pipe runs; in a city park it usually means tapping into the municipal supply.

Supply is only half of it. The other half is how quickly people can reach a tap. At Boston Calling 2024, attendees reported long waits at water refill stations, and organizers added more stations for 2025.¹²⁸

What powers a festival?

Mostly generators, and increasingly generators running on something other than fossil diesel. For 2023, Glastonbury said "all generators across the festival site," including the Pyramid Stage, would run on "palm oil-free HVO fuel - made from waste cooking oil," a renewable diesel replacement; some areas ran on solar PV and battery hybrid systems, and a temporary wind turbine powered some market stalls.¹²⁹ What HVO is, and how much it cuts emissions, is covered in the impact section.

Power is planned in zones: each stage, bar row, campsite and production compound gets its own supply, so a failure in one area does not take down the rest. Generators also need refueling on site, which puts fuel trucks on the same service roads as everything else during the build and the show.

The alternative is the grid. Powerful Thinking, a UK festival sustainability group, reports that Norway's Øya Festival (capacity 70,000) switched from diesel generators to grid power in 2010, and that the UK's Cambridge Folk Festival partly runs on mains power, saving 12,000-15,000 liters of diesel per event; it notes a new connection can be expensive, with costs sometimes shared by venues, councils or landowners.¹³⁰ In March 2026, Festival Republic unveiled a permanent mains supply in London's Finsbury Park to power the stage and other key areas at its events there, which it called a first for large-scale outdoor events in the UK.¹³¹

How are festival stages built?

Big festival stages are temporary demountable structures: steel or aluminum frames, roofs and towers bolted together on site and taken down afterward. In the UK, the HSE points organizers to Institution of Structural Engineers guidance on temporary demountable structures for detailed loading calculations.¹³² Wind is the load that matters most outdoors; the safety section covers what happened at the Indiana State Fair in 2011 when a temporary roof failed.

A stage is also a crowd-management decision. After 2000, Roskilde rebuilt its Orange Stage area with a larger, taller stage, zoned pits, and redesigned flow and escape routes.¹²² A taller stage means people further back can see, which takes pressure off the front.

For the gear that goes on and around a stage - rigging, lighting, audio, video - the sister guide at https://showfile.cold.fyi/ goes deeper.

Why is there a gap between the crowd and the stage?

That gap is the pit, and the fence in front of it is the front-of-stage barrier. According to the HSE, the barrier is built on a load-bearing "A" frame in steel or aluminum, with sections "around 1200mm high and 1m wide" (about 4 feet by 3 feet). The audience stands on a footplate, which uses their own weight to hold the barrier down; staff work from a rear step. There should be "no access gates on pressured sections."¹³²

The HSE favors curved barrier layouts. A curve creates more distance to the stage, a wider pit for "stewards, first-aiders and paramedics," and helps in "dissipating audience surges away from the centre." The guidance warns against pockets where people can get trapped and calls for escape routes on both sides.¹³²

Large crowds are often split further. A finger barrier runs back from the front into the crowd, and the HSE says it must take the same load as the front barrier.¹³² A zoned pit system uses multiple barrier lines to divide the area in front of a big stage into pens. Roskilde introduced one at its Orange Stage and Arena after 2000, along with "systematic crowd monitoring" by trained observers.¹²²

In the US, the closest equivalents are ANSI-approved standards written by ESTA, the Entertainment Services and Technology Association. ANSI ES1.9, Event Safety - Crowd Management, was approved in July 2020 and covers the basic principles and vocabulary of crowd management.¹³³ It was followed in 2023 by ES1.40, Event Safety - Security, and a revised E1.21 for temporary outdoor structures.¹³⁴

Does a festival need a license?

Yes, though which ones depends entirely on where it is.

In the UK, the Purple Guide covers the Licensing Act 2003 alongside health and safety, civil contingency and fire law.¹²¹ Licensing is handled by local councils, which is why so much practical event guidance in this section comes from council websites.

Under the Licensing Act 2003 in England and Wales, every license decision turns on four objectives, which Gravesham Borough Council lists as "of equal importance": the prevention of crime and disorder, public safety, the prevention of public nuisance, and the protection of children from harm.¹³⁵ Many councils also run a Safety Advisory Group (SAG) of council, police, fire, ambulance and highways officers. Surrey Heath's SAG, for example, advises organizers of large or unusual events, and its members "will not accept or adopt any of the responsibilities of the organiser."¹³⁶

In the US, there is no national festival license and no single national equivalent of the Purple Guide. Cities and counties issue the event, entertainment and alcohol permissions. After Astroworld, the Texas Task Force on Concert Safety (April 2022) recommended that municipal mass gatherings follow state permit guidelines, that local authorities stop events held without a permit or beyond its terms, and that the state produce a universal permit template and checklist for County Judges, plus an online Event Production Guide.¹³⁷

In Boston

Boston Calling, held at the Harvard Athletic Complex in Allston since 2017 according to Wikipedia, is the city's worked example.⁹ It did not run in 2026. When organizers announced the hiatus in June 2025, they named June 4-6, 2027, for the next edition,⁹ but Axios reported in October 2026 that the return was in doubt as organizers stayed silent; the New England section has the details.¹³⁸

Its layout changes with experience. For 2025, the festival merged its Green and Red stages into a rotating stage system to improve sightlines and movement, published a revised site map, and added water stations after 2024 complaints about refill lines.¹²⁸ Those changes followed the crowding on Sunday, May 26, 2024, covered in the safety section.

On licensing, the City of Boston Licensing Board issued an advisory on August 23, 2024, reminding licensees that they may not hold events "outside the scope of their license without explicit approval from the Board," must follow closing hours, capacity and premises terms, and face penalties up to suspension or revocation.¹³⁹ That advisory is aimed at licensed premises, but it shows the principle: in Boston, the license defines what you can do and where.

Elsewhere in the world

• UK: The Purple Guide (Events Industry Forum, since 2012) is the shared reference; Glastonbury is the best-documented build, from three-month stage builds to mid-May phone masts.¹¹⁹¹¹⁷
• Denmark: Roskilde rebuilt its main stage area after 2000 and helped spread the HSE guide; Denmark published a national concert safety guide in 2002.¹²²
• US: Permits are local. Texas has gone furthest toward a state template, with its 2022 task force report and Event Production Guide.¹³⁷

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