Shelter Emergency Exit: Hatch or Full-Size Door?

A shelter entrance and emergency exit must protect the structure while allowing occupants to leave it quickly and as safely as possible after an incident. These two requirements are not always easy to reconcile. A compact hatch connected to a fixed vertical ladder requires little space and may be justified in a small shelter. However, this does not mean that every occupant will be able to use it.

An opening approximately 600 mm wide can become a serious obstacle for an older person, someone with reduced mobility, an injured occupant, a person of larger body size or an adult attempting to evacuate with a child. The access and escape arrangement should therefore not be selected solely on the basis of the space available. The starting point should be a different question: who will actually use the shelter, and in what condition might they have to leave it?

Why can a hatch and ladder become a problem?

A typical compact emergency exit may consist of an escape shaft, a fixed vertical ladder and a steel hatch. This arrangement reduces the floor area required for circulation and can provide a secondary means of escape. It also has important limitations.

Climbing a ladder requires functional arms and legs, sufficient grip strength, balance and the ability to bend the knees and hips. The occupant must then pass through the opening, reposition their body and operate the closure. Even under normal conditions, not everyone can complete these actions without assistance.

After an emergency, the situation may be considerably more difficult. Shelter occupants may include people who are:

injured, exhausted or physically weakened;
using crutches or a wheelchair;
older and experiencing reduced strength or balance;
living with a prosthesis, limited joint mobility or cardiovascular disease;
responsible for small children who require assistance;
wearing protective clothing or respiratory protective equipment;
operating in darkness, under stress, in smoke or with limited visibility.

It is unsafe to assume that someone who entered the shelter independently will also be able to climb a ladder after an incident. An occupant may have been injured, may be exhausted or may need to assist another person.

Is a 600 mm opening wide enough?

The stated size of a hatch does not by itself determine whether it is functional. It is essential to establish whether 600 mm refers to the overall product dimension, the structural opening or the actual clear opening after the frame, hinges and locking mechanism have been taken into account.

Even a true clear opening of 600 mm creates a bottleneck. It may be impossible for a wheelchair user to pass through and extremely difficult for people with reduced mobility. It also restricts assisted evacuation, the removal of an injured person and the movement of essential equipment.

This does not mean that every hatch of this size is inherently unsuitable. It may be appropriate as a secondary exit from a small shelter intended for a known group of physically capable occupants. It should not, however, be treated as a universal solution, particularly in public shelters, workplaces, multi-residential buildings or facilities intended for larger groups.

People with functional limitations are not a marginal group

Designing only for a young, fully able-bodied occupant excludes a substantial proportion of potential shelter users. Available statistics illustrate the scale of the issue:

Country	Data on disability or functional limitations
Poland	According to the 2021 National Census, approximately 5.45 million people, or 14.3% of the population, were persons with disabilities.
Germany	Approximately 13 million people – slightly more than one in six residents – live with a recognised disability or impairment. At the end of 2025, approximately 7.8 million people, or 9.4% of the population, had a formally recognised severe disability.
Switzerland	Approximately 1.73 million people aged 16 or over, representing 20% of that age group, met the survey definition of a person with a disability. Around 325,000 were severely limited in everyday activities.
Finland	In 2025, approximately 591,000 people aged 16 or over, or 12.7% of that age group, had considerable difficulty with at least one basic activity. Among people aged 65 or over, this applied to approximately 286,000 people – around 22% of older people living in private households.

These figures should not be compared directly. The countries use different definitions, age groups and research methods. The overall conclusion is nevertheless clear: functional limitations affect a significant proportion of potential shelter occupants. A person does not need to hold a formal disability certificate to have difficulty using a hatch. An injury, recent surgery or temporary physical weakness may be enough to make a ladder inaccessible.

A full-size door and stairs as an alternative

Where the site conditions and structural design allow it, a secondary exit with a full-height protective door and stairs may provide an alternative to a hatch and ladder. This arrangement requires more space but can significantly improve accessibility and evacuation performance.

Its main advantages include:

easier movement for older people and occupants with reduced mobility;
the possibility of providing handrails, landings, emergency lighting and slip-resistant surfaces;
more room to assist an injured person;
easier movement of children and essential equipment;
lower requirements for upper-body strength, grip and coordination than a ladder;
more efficient evacuation of a larger group.

One limitation must be stated clearly: stairs are more accessible than a ladder, but they do not create a barrier-free route. A wheelchair user may still require assistance, an evacuation chair or another measure included in the emergency plan. Where the topography permits an exit at a similar level, a horizontal escape route or properly designed ramp should be considered. A lift should not be the sole means of evacuation because it may become unavailable following a power failure or damage to the installation.

A full-size door does not solve every problem

Replacing a hatch with a door cannot be reduced to simply enlarging the opening. The secondary exit remains part of the shelter’s complete protective system. The design should consider:

the resistance required from the closure under the loads and hazards specified for the shelter;
the airtightness of the door and the connection between its frame and the structure;
protection of the escape route against direct blast-wave exposure;
the risk of the exit being blocked by debris, snow or damaged structural elements;
the opening direction and the clearance required to operate the door leaf;
drainage of the shaft or stairwell and protection against flooding;
protection against smoke and hazardous substances entering the shelter;
manual operation without electrical power;
emergency lighting, signage, handrails and slip-resistant surfaces;
sufficient separation between the main entrance and emergency exit so that a single event cannot block both routes.

Depending on the shelter’s purpose, the design may also require a protective vestibule, an offset or change in direction along the access route, an additional closure or other protective measures. The final arrangement should follow from the structural design, hazard analysis, expected occupancy and the requirements applicable in the country where the shelter is built.

When is a hatch appropriate, and when should stairs be considered?

A hatch and ladder may be a rational solution when:

they provide only a secondary means of escape;
the shelter is small and intended for a defined group of physically capable occupants;
space constraints make a stairwell impracticable;
the clear opening, operating method and location have been selected for the actual users;
a method of assisting anyone unable to climb the ladder independently has been planned.

A full-height protective door and stairs should be considered particularly when:

occupants may include older people, children or persons with disabilities;
the facility is intended for residents of a multi-residential building, employees or members of the public;
a larger group may need to use the exit;
the route may be needed to assist or transport injured occupants;
broad accessibility and efficient evacuation are design priorities.

Design for real occupants, not an idealised user

An emergency exit is needed precisely when normal conditions no longer exist. It should therefore not be designed solely around a healthy, physically capable person operating without stress. The design must also account for an older, injured, weakened or mobility-impaired occupant, as well as someone assisting a child.

A hatch approximately 600 mm wide and a fixed vertical ladder may be technically justified, but for some users they will form an impassable barrier. A full-size protective door and stairs require more space and a more developed structure, yet in many shelters they can provide a substantially more functional escape route.

The right solution cannot be selected from a single dimension or a standard catalogue layout. It should result from a proper assessment of the hazards, structural conditions and abilities of all people who may need to use the shelter.

Statistical sources

Note: Access routes and protective closures should always be selected as part of a properly engineered design by suitably qualified professionals, taking account of the shelter’s purpose, hazard analysis and the regulations applicable at the project location.

Shelter Emergency Exits: Hatch and Ladder or Door and Stairs?