The short answer
On a large site, place AEDs and first-aid points by response time rather than floor area: a trained responder should be able to fetch a device and return within roughly three minutes, which typically means keeping an AED within a 90-second walk (about 150–200 metres) of the highest-risk zones. Start by mapping the territory and its risks, then position devices at busy thoroughfares and distant dead ends, and back every cabinet with clear signage, training, and registration.
Key takeaways
- Anchor placement to the collapse-to-shock window of roughly three to five minutes recommended by organisations such as the AHA and Resuscitation Council UK, not to square footage alone.
- Plan from a site map and risk heat-map: hot and electrically hazardous work areas, remote corners and high-traffic gathering spots outrank grand entrances.
- On multi-shift sites, coverage must reflect where people actually are at night and on weekends, and access should be simple even when no one is formally on duty.
- A UK Resuscitation Council guidance positions AEDs where the public and staff can reach them quickly, recommends registering devices on the national defibrillator network, and advises storing only the device and its kit in the cabinet.
- Training should target the people who will physically arrive first in each zone, with annual refreshers, because skills fade and the AED is only as useful as the responder who knows where it is.
- Maintenance is a scheduled task: battery and electrode expiry, self-test indicators, unobstructed access, and signed logs that prove the programme is working.
- For regulated first-aid provision, remember that rules differ by country and sector, so pair general best practice with your local occupational safety and medical requirements.
Plan by response time, not by floor area
In sudden cardiac arrest, survival falls sharply with every minute without defibrillation, which is why AHA-based guidance and Resuscitation Council UK materials treat early shock alongside good CPR as the deciding factor. On an open site or large building, that translates into a practical benchmark: a trained person should be able to reach the AED, pick it up and return to the casualty within roughly three minutes in total.
A brisk walking pace of around 1.2–1.4 metres per second means a person covers roughly 100–130 metres in a 90-second outward leg, and with the return journey one device realistically serves a radius of about 150–200 metres around likely incident points. Square metres alone are a poor guide: two warehouses of identical size can need different numbers of devices because of racking, mezzanines, doors and headcount.
The same time-to-reach logic already drives placement of fire extinguishers and eyewash stations, so it adapts naturally to AEDs and first-aid points. Because layouts vary, treat published figures as a starting point and confirm them with stopwatch drills on your own floor rather than trusting a generic rule.
- Reference point: defibrillation delivered within roughly three minutes of the collapse.
- Working rule: an out-and-back fetch trip no longer than ~90 seconds.
- Model real routes between incident zones and device cabinets, not the floor plan alone.
- Count vertical travel and gate delays separately on multi-level or gated sites.
Map the territory and prioritise by risk
Start with a site plan and mark zones where cardiac arrest is more likely or where help arrives late: heat-stressed and physically demanding production areas, locations with electrical hazards and grounding, canteens and reception points with high footfall, and remote dead-end sections that emergency vehicles cannot reach quickly. Then overlay your existing AEDs, first-aid kits and medical rooms and look for coverage gaps.
Priority goes to where people actually are and where external response is slowest, not to the most prestigious entrance. On a typical warehouse this often means two to three devices: one near the main entrance, one deep inside the main racking bay, and one in the loading area. For multi-building campuses, treat each structure and the gaps between buildings as separate coverage problems.
Remember that an AED is designed for bystanders with little or no training: it analyses the rhythm and will not deliver a shock unless one is indicated. The real obstacle is usually access and awareness, so a visible, unlocked cabinet beats a hidden device behind a reception desk or a key that nobody can find quickly.
- Draw a heat-map of risk: workload intensity, heat, electrical exposure, footfall.
- Check real ambulance arrival times to each remote point on the site.
- Place devices at high-traffic points and at long-march dead ends.
- Treat shift work as a separate problem: night and weekend occupancy differ.
Where first-aid points and regulation enter the picture
AED placement is only half the system. First-aid points and kits must sit where the delay to treatment would otherwise be long, and their contents are usually prescribed by regulation. In the United States, OSHA has no dedicated AED standard but expects each workplace to assess its own AED needs within its first-aid response; its Medical Services and First Aid rule at 29 CFR 1910.151 requires adequate training for people who render first aid when no hospital or clinic is nearby, which extends to those expected to use an AED.
In the United Kingdom, Resuscitation Council UK advises organisations to make school and community devices available 24/7 where feasible and to register each device on The Circuit, the national defibrillator network, so ambulance call handlers can direct callers to the nearest rescue-ready unit. The Council also recommends keeping only the AED and associated equipment inside the cabinet so nothing distracts from CPR or defibrillation.
Regulatory triggers for dedicated rooms also vary by country and sector; for example, some jurisdictions require a designated medical room or first-aid room beyond a certain headcount. Because laws, state requirements and building codes differ and change, treat this article as general guidance and confirm the applicable occupational safety and medical obligations for your jurisdiction before finalising a layout.
- OSHA (US) expects a workplace to assess its own AED needs as part of first aid.
- UK guidance: register AEDs on The Circuit and keep them accessible outside core hours where possible.
- Store only the device and its kit in the cabinet.
- Check sector- and country-specific rules on first-aid rooms and minimum training.
Access, signage and around-the-clock availability
Devices and first-aid points should be visible from a distance, clear of racking and machinery, and close to evacuation routes and gathering points. Directional signage from every entrance matters as much as the device itself, because in a real emergency people under stress will look for the sign, not the equipment list. Mount cabinets at a height that allows quick removal and away from loading bays and vehicle traffic where they could be damaged.
On sites that operate outside normal hours, plan for that reality: either keep the device in an unlocked area that is genuinely staffed, or install an outdoor-rated cabinet with protection from dust and moisture and a simple, well-understood opening mechanism. Resuscitation Council UK specifically encourages 24/7 public access where a device serves a whole community, and the same logic applies to campuses and shift-work plants.
Registration closes the loop: provide the site coordinates of every AED to the local emergency services so a dispatcher can guide a caller to the nearest unit. Re-verify coordinates whenever equipment is moved during reconfiguration, because a cabinet that quietly relocates in a refit can disappear from the emergency database and from everyone's mental map.
- Device visible from main aisles and never blocked by stock or vehicles.
- Signage from every entrance using standard AED pictograms.
- Out-of-hours occupancy justifies its own coverage and cabinet access plan.
- Coordinates registered with emergency services and re-verified after any move.
- Only the device and associated equipment stored in the cabinet.
Training, maintenance and proving readiness
A correctly placed AED is only useful if people know it exists, are willing to use it and have rehearsed their roles. Identify who physically arrives first in each zone and shift, train those people in CPR and AED use, and make sure callers know who summons emergency services and who fetches the device. Skills fade quickly, so refresh CPR and AED practice annually and cover device locations in new-hire induction.
Maintenance is a scheduled duty, not an afterthought: check the device's self-test indicator, replace batteries and electrodes before their expiry dates, and keep first-aid kits within the expiry of their contents. Record every check with a date and the responsible person's name so an audit or an inspection shows a documented history rather than good intentions.
Run a full-scale drill once a year: stage a call in the farthest part of the site and time how long it takes for a responder to arrive with the AED and start chest compressions. This is the only reliable way to confirm that the theoretical three-minute benchmark holds on the actual layout, through real doors, lifts and gates.
- Assign a named owner for checks and replenishment in each zone.
- Annual refreshers in CPR and AED for front-line responders.
- Monthly verification of self-test indicators and expiry dates.
- Annual timed drill from the most distant incident point.
- Signed maintenance log to evidence a working programme.
Put it into practice
Large-site first-aid and AED readiness audit
Walk each zone of your site (main building, remote blocks, warehouse, loading dock, canteen, night-shift areas) against this checklist and answer yes or no. Every 'no' becomes an action item with an owner and a deadline.
- Is there an up-to-date site map showing every AED, first-aid kit and medical room, with ambulance response times marked per zone?
- Does every AED cover roughly 150–200 metres (a ~90-second out-and-back trip) around areas where people are present?
- Are all high-risk areas — hot and electrical work zones, remote dead ends, high-footfall gathering points — inside a device's coverage?
- Is every device visible from the main aisle, and do signs lead to it from every entrance?
- Is the device reachable outside normal hours without hunting for a key or code?
- Are first-aid kits stocked according to your applicable regulation, and has nothing in them expired?
- Has each AED passed its self-test in the last month, and is the result recorded?
- Are batteries and electrode pads within their expiry dates and stored correctly?
- Do duty staff and front-line workers know where the devices are and who among them is trained?
- Are AED coordinates registered with the local emergency service and still accurate after any moves?
- Has a timed drill been run in the last year from the most distant point on site?
- Is a named owner in place for checks and replenishment, with a signed log to prove it?
Questions people ask
How far apart should AEDs be placed in a large warehouse or plant?
Judge spacing by travel time, not distance. The working benchmark is to deliver defibrillation within roughly three minutes of collapse, which typically means a responder can fetch a device and return in about 90 seconds. At a brisk walking pace of roughly 1.2–1.4 m/s that gives one device a practical coverage radius of about 150–200 metres around likely incident points. Because racking, mezzanines, doors and gates add time, verify the real number of devices with stopwatch drills on your actual layout rather than relying on a generic rule.
How many AEDs does a large site need?
There is no universal number, because need follows headcount distribution, floor layout and shift patterns rather than square metres alone. A reasonable starting plan is one device at each main entrance, one in the deepest part of the main working area, and one at any remote, high-risk or high-footfall zone that sits more than a 90-second out-and-back trip from another unit. Large multi-building campuses and multi-level facilities usually need more units. Confirm coverage by timing how long it takes a trained responder to reach the device and return from every point on the site.
What are the regulatory requirements for AEDs in workplaces?
Requirements vary by country and state. In the United States, OSHA has no dedicated AED standard but expects each workplace to assess its own AED needs as part of its first-aid programme, and its Medical Services and First Aid rule (29 CFR 1910.151) requires that people who render first aid when no hospital is nearby be adequately trained, which includes those expected to use an AED. In the UK, Resuscitation Council UK recommends registering devices on The Circuit so ambulance call handlers can locate them. Always confirm the rules for your jurisdiction and sector before finalising a programme.
Who should be trained to use an AED on a large site?
Train the people who will physically arrive first at an incident in each zone and shift, ideally combined with a CPR course. In practice that includes supervisors, floor leads, security and loading-dock staff spread across the site so that a trained responder is always within reach of a device. Because skills fade, refresh CPR and AED practice annually and cover device locations during new-hire induction. Remember that an AED is designed for laypeople with minimal training, so training mainly builds confidence, speed and correct sequencing rather than complex clinical skill.
How do I ensure an AED is accessible outside normal working hours?
Match coverage to real occupancy. If only part of the site is staffed at night or on weekends, place a dedicated device and trained responder coverage in that area rather than relying on one device at the main entrance. For around-the-clock access, keep the device in a genuinely unlocked and supervised area, or install an outdoor-rated cabinet with dust and moisture protection and a simple opening mechanism. Resuscitation Council UK encourages 24/7 availability where a device can also serve the wider community. Rehearse the after-hours scenario in a drill to confirm the plan actually works.
Sources and further reading
Sources were checked when this page was generated. Confirm changing dates, rules and prices with the original publisher.
- Guidance: Defibrillators (Resuscitation Council UK)Resuscitation Council UK
- Updated AED guidance empowers communities to save livesResuscitation Council UK
- A Standardized Process to Determine Appropriate and Effective Placement of Automated External DefibrillatorsOccupational Health & Safety
- AEDs in the workplaceJ. J. Keller
- Get St John Safe: a guide to setting up defibrillators in your workplaceSt John Ambulance Western Australia
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