National normative requirements
First, GB51251-2017 "building smoke prevention and exhaust system technical standards"
Fire resistance limit requirements for parts of the duct:
1, smoke prevention system
2, smoke exhaust system
3, make-up air system
Second, GB50016-2014 "Building Design Fire Code" (2018 version) Code for Fire Protection of Building Design (2018 Edition)
1, the fire resistance limit requirements for air ducts that pass through the fire separation.
2. Usually, the fire resistance limit of fire partition wall is 1~3h; the fire resistance limit of floor slab is 1.5h; and the fire resistance limit of fire wall is not less than 3.0h.
3. "Enhanced Technical Requirements for Fire Protection Design of Civil Buildings of Building Height Greater Than 250 Meter" The fire resistance limit of fire fighting ducts that horizontally pass through fire protection partitions or refuge areas should meet 1.5h.
4. "Building Discharge Smoke exhaust system technical standards," the provisions of the note clearly points out that the air supply ducts, smoke exhaust ducts to meet the fire-resistant limit provisions for mandatory provisions, must be strictly enforced.
Local specification requirements
The local requirements for the implementation of the fire-resistant limit of the duct compared to the national standard have been strengthened to varying degrees.
1. "Sichuan Province, the implementation of technical standards for building smoke and smoke exhaust system rules"
2. "Zhejiang Province, the operation of the fire technical guide to the difficult issues 2020 edition"
◆ Pressurized air supply ducts through the fire partition should meet the fire resistance limit of 1.50h.
◆ Through the refuge area of the duct should also meet the different fire resistance limit.
3. "Technical Guidelines for Smoke and Smoke Exhaustion in Buildings in Sichuan and Chongqing Areas"
Frequently Asked Questions about Smoke and Smoke Exhaustion Adiabatic Ventilation Ducts:
(1) Is it possible to ensure the fire-resistance limit of the galvanized steel air ducts?
According to GB 50016-2014 "building design fire code" (2018? edition) the definition of fire resistance limit:
Fire resistance limit contains bearing capacity, integrity and thermal insulation, galvanized steel can not meet the thermal insulation, in the event of fire, whether the bearing capacity to meet the relevant test report, so the galvanized steel is not recognized to meet the fire resistance limit even 0.5h, so in order to meet the air ducts, the galvanized steel can not meet the fire resistance limit, so in order to meet the fire resistance limit, the galvanized steel is not recognized. Fire limit, so in order to meet the fire limit requirements of the duct, galvanized steel duct is required to take certain measures.
For example, the requirements are set out in the "Zhejiang Province Fire Protection Difficult Problems Operation Technical Guide 2020 Edition".
(2) Can it be made of non-metallic fire-resistant sheet?
Regardless of the measures taken, it should meet the class A non-combustible, with the fire-resistance limit test report issued by the National Center for Quality Supervision and Inspection of Fire-Resistant Building Materials. And GB50981-2014 "Building Electrical and Mechanical Engineering Seismic Design Code" requires that the smoke duct should or should be made of galvanized steel.
Guangdong Province, "building smoke exhaust system technical standards," the question of interpretation also requires smoke duct to use metal duct.
(3) anti-smoke exhaust duct fire-resistant limit of 0.5h, 1h, 1.5h should be how to do, to specific practices?
3.3.8 Mechanical pressurized air supply duct setup and fire-resistant limit should be in accordance with the following provisions:
0.5 hours of steel plate duct can be satisfied directly, 1 hour need to take thickening or thermal insulation 20 ㎜, 1.5 hours of 50 insulation thickness and standard steel plate duct, inorganic glass fiber reinforced plastic duct or glass fiber wool board made of super duct.
You can refer to the "Technical Regulations for Fire Protection of Building Steel Structure" Article 3.0.1 The data in the table of various types of steel components, combined components, etc. can meet the requirements of the fire-resistance limit by using fireproof coating.GB51249-2017 Article 4.1.2: The fire protection of the steel structure can be protected by one of the following measures or several of them in the compound (group):
1. Spraying (wiping coating) Fireproof coating;
2, wrapping fireproof board;
3, wrapping flexible felt heat-insulating materials;
4, outer wrapping concrete, metal mesh plastered mortar or masonry masonry.
How many practices of duct fire resistance limit?
First, the fire board + insulation cotton + galvanized steel plate
20K607 "smoke and HVAC fire protection design review and installation" atlas on the steel duct fire protection example of wrapped industrial integration of calcium silicate board (i.e., fire prevention board) of the practice, from the point of view of the market research, this is also the most common and common practice:
But according to the customer's feedback, the use of Fireproof board + thermal insulation cotton + galvanized iron and other conventional practices, the process is more complex, more materials, the cost is also higher.
(Note: According to the specification, such as the ceiling without combustible materials, can not be insulated)
Second, the duct outside the high-temperature glass wool
Is there any other solution to reduce the cost of installation, reduce the process? Adiabatic microfiber products industry for smoke exhaust system in-depth study, only with special glass wool + duct can also reach the fire limit of 0.5 ~ 1.0h requirements to meet the smoke exhaust standards in most of the use of occasions, and in the project, which reduces the fire prevention board materials and its installation process, the cost will inevitably come down.
① 1.0h test report screenshot
② Shenzhen, a project site implementation photos
Third, the finished composite fire-resistant duct
At the same time, the company also provides a finished composite fire-resistant duct practice, the fire-resistant limit of the maximum 1.5h, 2.0h, 3.0h, the inner and outer layers of the different thicknesses of the color steel sheet plus the inner thermal insulation layer: