You can find out when a building is considered a special-purpose structure in Section 2(9) of the HBO.

These include, among others:

• High-rise buildings 22 meters or taller,
• buildings with a floor area of more than 1,600 m² on the floor with the largest footprint (excluding residential buildings, garages, and rooms and buildings used for bicycle parking),buildings with rooms located above the ground floor that are used for office or administrative purposes and
  a) individually have a floor area of more than 400 m² or
  b) are individually intended for use by more than 100 people,
• Retail establishments whose sales areas and shopping arcades have a floor area of more than 2,000 m²,
• Assembly venues with a capacity of more than 200 visitors,
• Hospitals and other facilities for the accommodation or care of children, the elderly, the sick, the disabled, or persons in need of assistance for other reasons,
• Daycare facilities for children with rooms used for children’s care located outside the ground floor,
• Restaurants and bars with a total floor area of more than 120 m² for guest areas or with guest areas not located on the ground floor totaling more than 70 m² in floor area,
• arcades with a floor area of more than 150 m²
• Accommodation facilities with more than 30 guest beds,
• Schools, universities, etc.
• Ancillary facilities and outbuildings for special structures,
• structural facilities whose use involves the handling or storage of substances posing an explosion hazard or an increased fire risk.

A full examination is carried out under building planning and building regulations law.
Under building planning law, the provisions of the Building Code and the regulations issued on the basis of the Building Code (development plans and conservation statutes) are examined.

Under building regulations law, the permissibility of a building project is assessed in accordance with the Hessian Building Code and regulations based on the Hessian Building Code (municipal statutes such as parking space, front garden or design statutes).

Exemptions or exceptions from building planning law must be applied for and justified separately in writing. This also applies to those deviations from building regulations that cannot be assessed and presented separately as part of an easement, for example in the fire protection concept. If no corresponding application has been submitted, even though the project deviates from substantive building law, the building application is incomplete. If there is a justified application for a deviation, exception or exemption, the building inspectorate decides at its own discretion.

In addition to the provisions of building regulations law, building planning law and other public law, the special building regulations must be observed.

Note
In contrast to all other building projects, the fire protection and stability of special buildings are inspected by the building inspectorate or by officially appointed inspection engineers.

Soil protection
Approval of measures on properties with soil contamination or building contamination (contaminated sites) by the higher soil protection authority.

Construction must begin within five years of the building authority issuing the permit. The building permit expires at the end of the five-year period. It also loses its validity if construction work has been suspended for two years.

The building permit may be extended for up to two years at a time upon request. This request may be submitted informally to the building authority, citing the file number. Please ensure that the request is received by the building authority in a timely manner before the building permit expires. An extension is generally no longer possible if legislative changes have occurred in the meantime or if other framework conditions have changed.

Structural engineering certificates and attestations:
The scope of the certificates and evidence to be submitted with the completion notices depends on the type of use and the associated safety-related systems and facilities. The submission of certain certificates for final completion is also often stipulated as a condition in the building permit.