Expert opinion on escape routes

The workplace regulation ASR A2.3 gives guidelines for the dimensioning of escape routes and is currently being updated by the Committee for Workplaces (ASTA). As part of this revision, an expert opinion was prepared by accu:rate GmbH and IST GmbH: With the aid of two independent microscopic simulation models, the extent to which constrictions and stairs on escape routes as well as staggered use of escape routes influence the escape time was investigated.

Testing of ASR A2.3

To ensure the safety and protection of the health of employees when setting up and operating workplaces, the employer must take precautions to ensure that employees can get to safety immediately in the event of danger and can be rescued quickly. An essential factor in this regard is the design of escape routes and emergency exits. In Germany, their number, arrangement and dimensions are regulated by the Technical Regulations for Workplaces ASR A2.3, which is published by the Federal Ministry of Labor and Social Affairs. Some of the requirements contained therein still originate from earlier directives. The Committee for Workplaces (ASTA) is therefore conducting a review and updating of ASR A2.3.

Aim of the review

In this context, accu:rate GmbH together with IST GmbH was commissioned to prepare the expert opinion on escape routes in workplaces - influence of route width, stairs, doors and constrictions on escape. The aim of this expert opinion was to make a statement on the factors influencing escape routes that affect the evacuation time. With the aid of two independent microscopic simulation models, the extent to which constrictions and stairways on escape routes, as well as staggered use of escape routes, influence escape time was investigated. Macroscopic model calculations were performed for comparison, and previous studies and data were compiled.

Results

The results show that short constrictions on horizontal paths have little effect on escape time. However, if longer constrictions are involved, such as those caused by office furniture, this has a significant effect on the evacuation time.

Vertical escape route elements (stairs) also have a significant influence on escape times, as they have a flow-reducing effect. Constrictions such as doors in front of stairs are therefore negligible, provided they are within the permissible range.

Furthermore, it was found that a time-delayed alarm system has a positive effect on the evacuation of the affected levels. Further investigations are required to define the required escape route width and to set it in relation to the number of persons per level. Finally, the largely linear correlation between the number of persons and the escape route width was also confirmed in this expert opinion. However, this is not yet reflected in ASR A2.3 point 5 para. 3. Here, there is a jump from 1.00 m escape route width for up to 20 persons to 1.20 m escape route width for up to 200 persons.

School building serves as reference project

As an additional scenario, a school building was considered to investigate the influence of the width of classroom doors on escape time. For this purpose, a school building was used that complies with the regulations of the Model School Building Code (MSchulbauR). The simulations clearly show that the width of the classroom doors in the 0.90 m and 1.20 m variants has no significant influence on the school's escape time; rather, the width of the stairs represents the dominant capacity bottleneck.

The results of the expert opinion serve the Escape Routes Project Group of the Committee for Workplaces (ASTA) as an important decision-making basis for the update of ASR A2.3.

The complete report can be downloaded here (in german).

Titelbild: Liane Metzler via Unsplash