capacity-and-safety

---
name: capacity-and-safety
description: Produces one dated file giving the number of people you may admit to each part of the venue for one event, the escape route arithmetic behind that number, who the responsible person is, the door counting method, and the numbered list of what is missing before you can sell a ticket. Use before you set a ticket allocation, before a night that will be busier than usual, or when nobody can say where the venue's capacity figure came from.
---

# How many people you may have in, and the evidence you were right

You give this the room measurements, the exit widths, what the night involves, the licence and any capacity already set by the fire and rescue service or the council, and who is running the door. You get back one dated file: the escape route capacity worked through with the arithmetic shown, the number you may sell against it, the responsible person named, the counting method and who holds the clicker, the event plan the fire guidance expects, and a numbered list of what is missing. It tells you what it could not verify rather than filling the gap, and it never signs off a number.

## What it does

1. **Name the responsible person in the legal sense before anything else, and write it down.** Article 3 of the Regulatory Reform (Fire Safety) Order 2005 defines it as, for a workplace, "the employer, if the workplace is to any extent under his control", and for other premises "the person who has control of the premises (as occupier or otherwise) in connection with the carrying on by him of a trade, business or other undertaking (for profit or not)" or, failing that, the owner. For a one off event with an outside promoter, a hired room or a marquee in the car park the answer is genuinely arguable, and it has to be agreed in writing before the night rather than after an incident. An unnamed responsible person is the most common gap in an event file and the most expensive.

2. **Find the existing capacity figure and its source before you calculate a new one.** A premises licence condition, a fire and rescue service letter, a previous fire risk assessment or a building control occupancy figure may already fix the number, and where one exists you work within it rather than around it. Record the document, its date, who issued it, and what it actually says, area by area. A number remembered from a conversation with an officer eleven years ago is not a source, and nor is a number the current manager inherited from the last one. Where no document can be produced, say so in the file in those words.

3. **Start the arithmetic from the exits, because the exits are what limit the room.** GOV.UK's guide for small and medium places of assembly gives the capacities directly: "A width of at least 750mm can accommodate up to: 80 people in higher risk premises; 100 people in normal risk premises; or 120 people in lower risk premises." And: "A width of at least 1,050mm can accommodate up to: 160 people in higher risk premises; 200 people in normal risk premises; or 240 people in lower risk premises." Then: "An additional 75mm should be allowed for each additional 15 persons (or part of 15)." Measure the effective width at the narrowest point, because "The effective usable width of an escape route is the narrowest point, normally a door or other restriction such as narrowing of a corridor due to fixtures and fittings."

4. **Discount the widest exit, every time, without being asked.** The same guide is explicit: "When calculating the overall available escape route capacity for premises that have more than one way out, you should normally assume that the widest is not available because it has been compromised by fire." It adds that where two exits are close enough that one fire could affect both, "it may be necessary to discount them both from your calculation." This single step is the difference between a capacity figure and a wish. It is also where most inherited venue numbers fail, because they were totalled across every door in the building including the one beside the kitchen.

5. **Cross check against floor area, and treat the lower of the two numbers as the answer.** For the standing parts of a venue the guide says: "In un-seated areas, foyers or bars you may estimate the maximum numbers based on a value of 0.3 to 0.5m2 per person." Work it at both ends and show both figures, because 0.3 and 0.5 give numbers that differ by two thirds and choosing the generous end without saying so is how a file becomes misleading. Note also that the guide states there should "normally be at least two escape routes from all parts of the premises, but a single escape route may be acceptable in some circumstances (e.g. a premises or part of a premises accommodating less than 60 people or where the travel distances are limited)." Where the floor area allows more than the exits, the exits win.

6. **Adjust for what this particular night is, rather than using the everyday number.** HSE's guidance on assessing crowd safety risks says "A key part of your assessment will be to determine the venue's safe capacity", and lists what to weigh when forecasting turnout: "previous attendance figures", "numbers visiting similar events", "advance ticket sales", "the level of publicity", and "variable factors, such as the likely effects of good or bad weather". It also notes that "the age range of a performer and the type of performance can help you predict behaviour". The places of assembly guide adds the factor a licensed venue must not skip: "you may also need to take account of the possible effects of intoxicants (alcohol, illegal drugs, etc.) on how people may react in a fire."

7. **Decide how you will count, who holds the count, and what happens when the number is reached, before the doors open.** The fire guidance names the method: "If the numbers of people entering the premises may be too great then procedures may be needed to control entry numbers, for example the use of tickets and clickers." HSE adds the arrival side: "Where the number of people arriving may exceed the safe capacity of the venue, you will need arrangements for monitoring and estimating the numbers of people arriving", and warns that you must "Ensure any security search procedures do not compromise the safety of people by creating an overcrowding risk." Write down the counting device, the named person holding it, how re-entry is handled, how smokers are counted, and the exact instruction when the number is hit.

8. **Write the event plan the guidance expects, and brief it, because a capacity number nobody acts on is decoration.** The places of assembly guide sets out what a temporary responsible person should know before an event, including "limitation on numbers of people", "any chains and padlocks which need removing from fire exits", "identification of key escape routes and exits", and "where people should assemble after they have left the premises". During the event it requires that "escape routes and exits do not become blocked", that "rooms do not become overcrowded", that "noise levels cannot drown out the fire alarm", and that "if necessary, the number of persons in your premises is limited or controlled". That last instruction is the one most often lost on a busy night.

9. **Record the assessment and date it, and check separately whether the night crosses a licensing or counter terrorism threshold.** Article 9 of the Fire Safety Order requires "a suitable and sufficient assessment of the risks to which relevant persons are exposed", reviewed "regularly so as to keep it up to date", and since the Building Safety Act 2022 amendment took effect on 1 October 2023 article 9(6) requires that "As soon as practicable after the assessment is made or reviewed, the responsible person must make a record of the assessment or review" with no five employee threshold. Then two separate questions. If the night runs under a temporary event notice, GOV.UK requires it to "have fewer than 500 people at all times, including staff running the event". And Martyn's Law, the Terrorism (Protection of Premises) Act 2025, will bring premises expecting 200 or more people into a standard tier and events expecting 800 or more into scope, but its duties are not yet in force; GOV.UK states "It is expected that the Act will come into force in spring 2027", so the file records the tier the venue will fall into and the date to prepare by, not a duty owed today.

## Then it checks

1. The responsible person is named for this event, with a line saying whether the agreement is in writing and who the other parties to it are.
2. Any pre-existing capacity figure is recorded with the document it came from, its date and its issuer, or the file states in terms that no document could be produced.
3. The escape route calculation shows the measured effective width at the narrowest point of each route, the risk rating used, the resulting capacity per route, and the total with the widest route removed.
4. The floor area cross check is shown at both 0.3 and 0.5 square metres per person, and the figure carried forward is the lower of the floor area result and the exit result.
5. The counting method names a device, a named person holding it, the treatment of re-entry and smokers, and the exact instruction at the point the number is reached.
6. The file is dated, states the source and read date of every figure quoted, and records separately whether the temporary event notice limit of fewer than 500 people applies and which Martyn's Law tier the premises will fall into when the Act commences.

Any check fails: name it, redo that step once. Failed twice: say what is wrong and stop.

## Rules
- Public information only.
- Never invent a fact, a number or a quote.
- Anything sent in someone's name says whose name it is. A capacity figure circulated to door staff names the person who set it.
- Never state that a venue is safe, compliant, or that a capacity figure is approved. Occupancy is settled by the responsible person's own fire risk assessment and, where they have set one, by the fire and rescue service or the licensing authority. This file prepares that work for them to check; it is not a determination and it is not a fire risk assessment.
- Refuse to produce a capacity figure higher than any figure already set by a licence condition, a fire and rescue service letter or a building control occupancy figure. Where the arithmetic suggests a higher number, the file records both and says the existing figure stands until the issuing body changes it.
- Never total the capacity of every exit without discounting the widest. A file that omits that step produces a number that is wrong in exactly the circumstances it exists for.
- Never take a measurement from a plan, a memory or a photograph. Effective widths are measured on site at the narrowest point with the door open at right angles, and any width not measured that way is listed as unverified.
- Never treat the everyday trading capacity as the event capacity. A seated dining room rearranged for standing, a marquee added, or a stage placed across an exit route makes it a different room.
- Never describe Martyn's Law as a duty the venue owes now. The Terrorism (Protection of Premises) Act 2025 received Royal Assent on 3 April 2025 and its main duties are not yet in force, and telling an owner otherwise sends them spending to a deadline that does not exist while leaving the fire duty that does exist unaddressed.
- This output is a working document prepared for the owner, their fire risk assessor, their licensing officer and the fire and rescue service to check before it is relied on. It gathers published guidance, shows the arithmetic and names the gaps. It is not a fire risk assessment, it is not a licensing decision and it does not certify that any number is safe.

## Built from
- The Regulatory Reform (Fire Safety) Order 2005, article 3, https://www.legislation.gov.uk/uksi/2005/1541/article/3, read 16 September 2026: the responsible person definition that step 1 forces the file to name.
- The Regulatory Reform (Fire Safety) Order 2005, article 9, https://www.legislation.gov.uk/uksi/2005/1541/article/9, read 16 September 2026: the suitable and sufficient assessment, the review duty, and the recording duty in article 9(6) as amended by the Building Safety Act 2022 with effect from 1 October 2023, all in step 9.
- Department for Communities and Local Government, "Fire safety risk assessment: small and medium places of assembly", https://www.gov.uk/government/publications/fire-safety-risk-assessment-small-and-medium-places-of-assembly, published 5 June 2006 and last updated 28 August 2024, guide PDF at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/973794/9294_Small_Mediumt_v2.pdf, read 16 September 2026: the exit width capacities and the 75mm rule in step 3, the discount the widest exit rule in step 4, the 0.3 to 0.5 square metres per person figure in step 5, the intoxicants factor in step 6, the tickets and clickers method in step 7, and the temporary responsible person plan in step 8.
- Health and Safety Executive, "Assess crowd safety risks and identify hazards", https://www.hse.gov.uk/event-safety/crowd-management-assess.htm, page updated 4 April 2025, read 16 September 2026: determining the venue's safe capacity and the turnout forecasting factors in step 6.
- Health and Safety Executive, "Put crowd controls in place", https://www.hse.gov.uk/event-safety/crowd-management-controls.htm, page updated 4 April 2025, read 16 September 2026: monitoring the numbers arriving and the search and overcrowding warning in step 7.
- GOV.UK, "Temporary Events Notice", https://www.gov.uk/temporary-events-notice, no publication date shown on the page, read 16 September 2026: the fewer than 500 people including staff limit in step 9.
- Terrorism (Protection of Premises) Act 2025, sections 2, 3 and 37, https://www.legislation.gov.uk/ukpga/2025/10/section/2, https://www.legislation.gov.uk/ukpga/2025/10/section/3 and https://www.legislation.gov.uk/ukpga/2025/10/section/37, read 16 September 2026: the 200 and 800 thresholds and the fact that Parts 1 and 2 commence by regulations rather than on Royal Assent, in step 9.
- GOV.UK, "Understanding Martyn's Law and the SIA's role as regulator", https://www.gov.uk/guidance/understanding-martyns-law-and-the-sias-role-as-regulator, published and last updated 17 July 2026, read 16 September 2026: the statement that the Act is expected to come into force in spring 2027, which is why step 9 and the Rules describe it as not yet in force.

# capacity-and-safety

## You are given
The event and the venue: the event date, what the night involves, the layout for that night area by area, and whether each area is seated, standing or mixed. For every area, the measured floor area in square metres and a list of its escape routes, each with the effective usable width measured on site in millimetres at its narrowest point, where that narrowest point is, whether the measurement was taken with the door open at right angles, and whether two routes are close enough that one fire could affect both. The risk rating already decided by the responsible person for each area, being `higher`, `normal` or `lower`. Any capacity already set by a licence condition, a fire and rescue service letter, a previous fire risk assessment or a building control occupancy figure, each with its issuing body, document reference and date. The responsible person for this event, whether the agreement is in writing, and the other parties to it. The door arrangements: the counting device, the named person holding it, how re-entry and smokers are handled, and the instruction at the point the number is reached. Whether a temporary event notice applies. And the judgements already made by Claude: the risk ratings applied, which routes are discounted and why, and which figure is carried forward for each area.

## Produce
Write into a `./capacity-and-safety-output/` folder:

1. `existing-capacity.csv` with these columns in this order: `area_name`, `figure_stated`, `issuing_body`, `document_reference`, `document_date`, `document_seen`, `wording_verbatim`. `document_seen` is `yes` or `no`. Where no document exists for an area the row is written with `figure_stated` empty and `document_seen` as `no`, and the area is listed in `gaps.md`.
2. `escape-routes.csv` with columns: `area_name`, `route_ref`, `route_description`, `effective_width_mm`, `narrowest_point_description`, `measured_on_site`, `measured_door_at_right_angles`, `risk_rating`, `base_capacity`, `additional_75mm_blocks`, `route_capacity`, `discounted`, `discount_reason`. `risk_rating` is exactly one of `higher`, `normal`, `lower`. `measured_on_site`, `measured_door_at_right_angles` and `discounted` are each `yes` or `no`. `discount_reason` is exactly one of `widest route`, `too close to another route`, `not discounted`.
3. `capacity-calculation.csv` with columns: `area_name`, `total_route_capacity_all_routes`, `widest_route_ref`, `widest_route_capacity`, `capacity_after_discount`, `floor_area_sqm`, `floor_area_at_0_3`, `floor_area_at_0_5`, `lower_of_the_two`, `existing_figure`, `figure_carried_forward`, `which_limit_binds`. `which_limit_binds` is exactly one of `escape routes`, `floor area`, `existing figure`, `licence condition`. `figure_carried_forward` is never higher than `existing_figure` where one exists.
4. `responsible-person.csv` with columns: `event_date`, `area_or_whole_premises`, `responsible_person_name`, `role`, `basis`, `agreement_in_writing`, `other_parties`, `date_agreed`. `basis` is exactly one of `employer with control of the workplace`, `person in control in connection with a trade or business`, `owner`, `not agreed`.
5. `door-control.csv` with columns: `area_name`, `counting_device`, `counter_name`, `counter_role`, `re_entry_method`, `smokers_method`, `instruction_at_capacity_verbatim`, `deputy_name`, `handover_times`. Any cell left empty places the area in `gaps.md`.
6. `threshold-check.csv` with columns: `threshold_name`, `figure`, `applies_to_this_event`, `status`, `source_url`, `source_read_date`, `date_to_prepare_by`. One row for each of: temporary event notice limit of fewer than 500 people including staff; Martyn's Law standard tier at 200 or more; Martyn's Law enhanced tier at 800 or more; Martyn's Law qualifying event at 800 or more. `status` is exactly one of `in force`, `not yet in force`, `not applicable`. Every Martyn's Law row carries `not yet in force`.
7. `gaps.md` - a numbered list of: any area with no responsible person named or no written agreement; any area with no existing capacity document; any escape route not measured on site or not measured with the door at right angles; any area where the widest route was not discounted; any area whose carried forward figure exceeds an existing figure; any area with fewer than two escape routes and a carried forward figure of 60 or more; any empty cell in `door-control.csv`; and any figure quoted without a source URL and read date.

## Rules
- Codex measures, records and checks. It never invents, never rewords the owner's wording, and never makes the judgement that was supplied to it. Quoted document wording is recorded exactly as written.
- Never state that a venue is safe, compliant or approved, never sign off a capacity, and never describe any output as a fire risk assessment.
- Never write a `figure_carried_forward` higher than an `existing_figure` where one exists. Where the arithmetic produces a higher number, record both, set `which_limit_binds` to `licence condition` or `existing figure`, and list the area in `gaps.md`.
- Never compute a capacity from a width that was not measured on site. Where `measured_on_site` is `no`, `route_capacity` is left empty and the route is listed in `gaps.md`.
- Never omit the widest route discount. Every area's `capacity_after_discount` is computed with the widest route removed, and where two routes were flagged as too close together both are removed.
- Never choose between the 0.3 and the 0.5 square metre figures. Both are computed and recorded, and `lower_of_the_two` compares the 0.3 result against the discounted escape route capacity.
- Never record a Martyn's Law row as in force. The Terrorism (Protection of Premises) Act 2025 received Royal Assent on 3 April 2025 and its main duties are not yet in force.
- Never estimate an attendance figure, a typical venue capacity, a crowd density benchmark or an industry average. Every number in every file traces to a measurement or a named document.
- Arithmetic is shown, not summarised: base capacity, the number of additional 75mm blocks and the resulting route capacity each occupy their own column so the sum can be checked by hand.
- Use British English, GBP and DD Month YYYY dates. No em dashes in any file you write, and any supplied wording containing one is recorded verbatim and flagged in `gaps.md`.
- Every file ends with this line: this is a working document prepared for the owner, their fire risk assessor, their licensing officer and the fire and rescue service to check before it is relied on. It is not a fire risk assessment, it is not a licensing decision and it does not certify that any number is safe.

## Return
The absolute path of each file written, the row count of each CSV, the figure carried forward for each area with which limit binds it, the total for the whole premises, every route not measured on site, the widest route discounted in each area with its capacity, the areas where the arithmetic exceeded an existing figure with both numbers, the areas with fewer than two escape routes and a figure of 60 or more, the named responsible person and whether the agreement is in writing, the named door counter and deputy for each area, the temporary event notice position, the Martyn's Law tier the premises will fall into with its status recorded as not yet in force, and the `gaps.md` item count.