The main function of the parapet in architecture is to provide waterproofing, which is often referred to as parapet flooding. For a general roof, after slope finding, heat preservation, heat insulation, waterproofing, etc. are completed, it will be about 250mm thick. Then consider rolling up the end of the waterproof layer to a height of 250mm, and the total parapet height will be 500mm (the practice in the 21st century is generally 600 or 700mm). high).
In the specifications, there are different requirements for this height in different places, and they are generally limited heights; after all, this is a non-structural component and is also an unsafe factor in the event of an earthquake.
As for other height statements, such as: no less than 1200mm, they consider the parapet as a safety protection, which is a departure from the original intention. To consider safety, you can build 600-high railings on the 600-high parapet as protection.
Increasing the height of the parapet out of thin air not only increases the cost, but also poses a safety hazard. It is better to use lightweight protective measures on the roof.
Code for anti-corrosion design of industrial buildings GB 50046-2008
Provisions: The roof form should be simple, and organized external drainage should be used. Buildings that emit a lot of corrosive dust during the production process should not have parapets.
Explanation: The purpose of using organized drainage is to prevent rainwater with corrosive media from overflowing and corroding the wall surface. Investigations show that after a parapet is installed on the roof of a building that emits a lot of corrosive dust, a large amount of dust accumulates on the parapet, which is difficult to remove and aggravates corrosion.
Seismic design and construction regulations for porous brick (KP1 type) buildings JGJ 68-90
Local size limits for porous brick houses (m)
6 degrees 7 Degree 8 degrees 9 degrees
The maximum height of the unanchored parapet (not at the entrance or exit) is 0.5; 0.5; 0.5; 0.0
Medium-sized block building design and construction specifications JGJ 5-80
Partial dimensions of block buildings (meters)
The maximum height of the unanchored parapet is 0.50. The parapet at the entrance and exit should be anchored
Building earthquake resistance appraisal standard GB50023-95
The construction of non-structural components should meet the following requirements. If they do not meet the requirements, they should be reinforced or take corresponding measures at the entrance or street frontage:
No tied parapets, facades and other decorations. When the strength grade of masonry mortar is not less than M2.5 and the thickness is 240mm, the height of its protrusion from the roof should not be greater than 0.5m for houses with poor integrity or non-rigid structures; it is not suitable for closed parapets of houses with rigid structures. Greater than 0.9m;
Safety Code for Engineering Design of Civilian Explosive Equipment GB 50089-2007
The structural treatment of the blast-resistant chamber and the main factory building shall comply with the following regulations:
1． When the anti-explosion room adopts a lightweight and fragile roof, the main factory roof adjacent to the anti-explosion room should not be higher than the roof of the anti-explosion room; when it is higher, the anti-explosion room should use a reinforced concrete roof. build.
2. When the explosion-resistant room adopts a lightweight and fragile roof, a reinforced concrete parapet should be set on the top of the reinforced concrete wall to separate it from the adjacent main factory roof. The height of the parapet should not be less than 500mm, and the thickness can be 1/2 of the wall thickness of the blast-resistant room, but should not be less than 150mm.
Building Design Code for the Elderly JGJ 122-99
For a roof platform or roof garden for the elderly, the height of the roof parapet guardrail should not be less than 1.10m; the roof protruding from the platform object, its height should not be less than 0.60m.