ISO 21927-4:2019 pdf free download – Smoke and heat control systems一 Part 4: Natural smoke and heat exhaust ventilators – Design, requirements and installation.
Furthermore, a maximum distance of 10 m and a minimum distance of 5 m between the outer NSHEVs and the external wall shall apply to NSHEVs installed in roofs. A maximum distance of 20 m and a minimum distance of 4 m between individual NSHEVs shall apply. The distances are measured from the outer edge of the outlet.
NSHEVs should not be installed in areas in which wind stagnation effects can be expected to occur (e.g. in the vicinity of rising walls).
7.2.3 Other elements of the building (e.g. surrounding roof structures or the cladding of smoke exhaust openings) shall not prevent NSHEVs from opening or reduce their geometrical opening area.
7.2.4 When remotely activated, all NSHEVs generally open at the same time. Manual activation of
NSHEVs shall be possible, as shall automatic activation.
For thermal activators, the static activation temperature should generally not exceed 72 °C.
The activation of NSHEVs and gas or water vapour extinguishing systems installed in a single space shall be coordinated.
It shall be ensured that fire gases are able to circulate freely around initiation devices that respond to smoke as well as heat.
It shall be possible to operate the manual initiation device from a safe place. The manual initiation device shall be safeguarded against being operated unintentionally. It shall be possible to see whether a manual activator has been operated and to identify which smoke reservoir it is assigned to.
Unintentional closing of NSHEVs during a fire shall be prevented.
Any cables to NSHEVs shall be installed such that they cannot be damaged or destroyed unintentionally.
7.2.5 Smoke barriers shall comply with ISO 2 1927-1.
8 NSHEVs combined with fire extinguishing equipment
In principle, it makes sense to combine water extinguishing systems (sprinklers) and NSHEVs since each system contributes in different and complementary ways to ensuring that certain protection goals are achieved due to their different mode of operation. However, in certain cases, there are limits to their combined use.
NSHEVs that open either by remote control (via a hand-held device) or automatically by initiation devices that respond to heat and where appropriate also to smoke can generally be combined with sprinkler or water-spray extinguishing systems. In the case of thermal initiation devices, NSHEVs can generally have the same activation temperatures as water extinguishing devices.
There are no restrictions on combining NSHEVs and ESFR sprinkler systems if the NSHEV is activated manually. However, a combination of NSHEVs and ESFR sprinkler systems is not appropriate if the NSHEV is activated automatically by means of smoke detectors. Special provisions apply if the NSHEVs are activated automatically by heat.
In cases in which NSHEVs and gas or water vapour extinguishing systems are installed in the same space, the automatic activation of the NSHEV shall be adapted to the requirements applying to such extinguishing systems.