YOSHINO GYPSUM | Basic knowledge on “gypsum” | Fire resistance, sound insulation, yield strength, and sound absorption | Why it will not burn? “Fire resistance”

Fire resistance

Reasons why gypsum is strong against fire

Gypsum is strong against fire. The secret is in crystallized water equivalent to about 21% of its weight.

This crystallized water is very stable in normal condition and does not disperse, but once it comes in contact with the heat of fire it will cause thermal decomposition and start to evaporate. The temperature of gypsum does not rise above a certain temperature until all of the crystallized water evaporates into water vapor and is released. To put it in simple words, imagine the same phenomenon that when you blow a flame with a burner onto a lump of ice, that part gradually dissolves into water and the ice temperature is kept below 0°C until all the ice melts.

Fire resistance regulations in the Building Standards Act

The fire resistance requirement for each part of fire resistant building is prescribed in Article 107 of the Building Standards Act Enforcement Ordinance.
Fire resistance requirement is classified into damage resistance, thermal insulation, and flame retardancy, and fire-resistant time is specified for each part.
According to the Building Standard Act, it regulates that fire partition compartments should be provided to prevent the spread of fire and the transmission of smoke.
It also regulates that columns and beams should be encased with fire resistant materials to prevent collapse of building due to fire.

Technical standard on fire resistance performance

Structural part			Fire resistant structure (Article 2 clause 7 of the Act)
			Floors where the number of floors counted from the top floor is more than 2 and less than 4, including the top floor itself (Article 107 of the Ordinance) A	Floors where the number of floors counted from the top floor is more than 5 and less than 14 (Article 107 of the Ordinance) B	Where the number of floors counted from the top floor is more than 15 (Article 107 of the Ordinance) C
Partition Walls	(Non-loadbearing wall)		1 hour	1 hour	1 hour
	(Limited to shear wall)		1 hour	2 hour	2 hour
Outer wall	Shear walls		1 hour	2 hour	2 hour
	Non-loadbearing wall	Parts where there are risk of fire spreading	1 hour	1 hour	1 hour
		Parts other than the above	30 minutes	30 minutes	30 minutes
Column			1 hour	2 hour	3 hour
Floor			1 hour	2 hour	2 hour
Beam			1 hour	2 hour	3 hour
Roof			30 minutes
Staircase			30 minutes
Related designated structure			Ministry of Construction Public Notice No. 1399 Year 200

* “Ministry of Construction” is the former name of the current “Ministry of Land, Infrastructure, Transport and Tourism (MLIT)”

Technical standard on quasi fire resistance performance

Fire partition

A section to prevent fire from spreading and to secure an evacuation route. (Building Standard Act Enforcement Ordinance, Article 112)

Fire partition

Regarding certification of fire resistance by the Minister of Land, Infrastructure, Transport and Tourism

Fire resistance of walls, floors, ceilings, pillars, etc. is certified by performing fire resistance tests at a public laboratory and satisfying certain criteria (fire resistance requirements).

Classification of fire resistance performance requirements

Damage resistance	Performance that does not cause deformation, melting, destruction or other damage
Heat insulation	Performance to prevent the temperature on the non-heated side rising above the ignition temperature of combustible matter
Flame retardancy	Prevents occurrence of cracks or other damage that will cause the fire to spread from the indoor side to the outdoors

List of certification numbers in relation to fire resistance

Go to fire resistance test page

Click here to return to the top of the page▲