In a previous blog article we looked at how a Fire Damper is classified, and how to interpret the classification. In this article we will look at how Smoke Control dampers are classified and how to interpret the classification.
The classification for Smoke Control dampers is covered by BS EN 13501-4:2016, however, before going into a detailed look at the classification, it is important to consider what a Smoke Control damper is.
A Smoke Control damper is a damper that is designed to allow the extract of smoke away from the fire and out to atmosphere. In order to achieve this it must:
- Drive to open or closed position in under 60 seconds
- No thermal release is allowed
- Maintain their position open or closed
- Have fire resistance in closed position (multi-compartment)
- Have known leakage characteristics (determining classification ‘E’ or ‘ES’)
- Maintain free area in the open position at elevated temperatures
Smoke Control dampers have their own harmonised product standard which is EN12101-8, test standard which is EN 1366-10 and classification standard EN 13501-4.
Shown below is an example of a Smoke Control Classification:
EI 90 (Vedw Hodw i ↔ o)S 1000 C10000 HOT 400/30 AA multi
E = Fire resistance integrity of the damper. This is mandatory, and is expressed as a function of time in minutes. It is determined by conducting a Fire Resistance test which is broadly inline with BS EN1366-2:2015, however, as the damper does not have a thermal release it must be initiated manually as part of the test. This initiation time is dependent on the type of classification that you are trying to achieve (AA or MA). Prior to the fire resistance or maintenance of opening tests commence the damper must be subject to its full cycle regime, during which the blades are weighted to replicate pressure resistance during the process.
Failure of the integrity criteria occurs when the damper leakage exceeding 360m³/hr/m² as the passage of excess hot gases is known to cause a secondary ignition, or sustained flaming on the non-furnace side of the test rig, or an opening appearing within the penetration seal or surrounding wall which would allow a gap gauge to be passed through.
I= Insulation rating of the damper. This is not a mandatory requirement for Smoke Control damper, but considerations should always be made to determine if it is required for the end application. As above this is determined during a Fire Resistance test to BS EN 1366-2:2015 and is expressed as a function of time in minutes.
Failure of the insulation criteria occurs when any one of the thermocouples exceed 180°C above ambient temperature, or the average temperature increase of all the thermocouples exceed 140°C above ambient.
90 = This is the time (in minutes), and is applicable to all of the criteria shown within the classification. There are set time categories as defined in the classification standard BS EN 13501-4:2016.
Ve = This shows that the damper can be installed in a vertical application.
More specifically, Vew shows that the classification obtained allows the damper to be installed inline with the wall, Ved shows that the classification obtained allows the damper to be installed vertically on a duct, whereas Vedw allows for vertical on duct and in wall.
This does not cover vertical blade axis of orientation, i.e. blades running vertically rather than horizontally.
Ho = This shows that the damper can be installed horizontally.
Very much as above, How shows the classification obtained allow the damper to be installed inline with the floor, Hod shows that the classification obtained allow the damper to be installed horizontally on a duct, and Hodw is horizontally on duct and in wall.
i↔o = ‘i’ defines inside, and ‘o’ defines outside of the furnace. The bi-directional arrow shows that the damper has been tested with fire exposure in both directions. Should the classification contain an arrow in only one direction this indicates that the fire exposure has only been tested from one direction.
S = Low smoke leakage rating of the damper. This is not a mandatory requirement to achieve a damper classification, but considerations should always be made to determine if it is required for the application.
Failure of the reduced smoke leakage criteria occurs when the damper leakage exceeds 200m3/hr/m2, during the fire resistance test, and ambient leakage test.
1000 = This is the general system pressure level (in Pascals) that corresponded to the under-pressure level used during the test.
- 1500Pa general operation = 500Pa during Test
- 1000Pa general operation = 300Pa during Test
- 500Pa general operation = 150Pa during Test
C10,000 = This is the number of cycles that the damper is test to which is relative to a dampers intended use:
- C300 = Smoke control only systems (300 cycles)
- C10,000 = Combined smoke control and environmental systems (10,000 Cycles +100 at 15% over voltage +100 at 10% under voltage)
- Cmod = modulating dampers used in combined smoke control and environmental systems, respectively. (20,000 Cycles)
If the damper is intended to operate under system pressure (when the fans are running) then the cycle tests need to be conducted with weighted blades.
HOT400/30 = This is another optional requirement and is the ability of a damper to repeatedly open and close at a temperature of 400°C for 30 mins, after which the furnace temperature is increase to the standard cellulose time temperature curve and the test continues for another 30mins. There is no leakage criteria for the test.
AA = This section of the classification defines the method of activation and can either be AA or MA.
- AA = Automatic Activation.
- MA = Manual Intervention.
Multi = This section of the classification defines if the damper is a Multi-compartment or Single compartment damper:
- Multi – Smoke control dampers for use in multi compartment areas, which may be associated with smoke control duct tested according to EN 1366-8.
- Single - Smoke control dampers for use in single compartment areas, which may be associated with smoke control ducts tested to EN 1366-9.
Single compartment dampers will have their E classification listed as E600. This mean that the dampers Fire Resistance Test is limited to 600oC and not the cellulosic fire test curve which is used on standard Fire Resistance Tests. For this reason a single compartment Smoke Control damper must not be used for fire compartmentation or within multi-compartment ductwork system (EN1366-8), however, it is acceptable to use Multi-compartment dampers within both Single and Multi-compartment ductwork systems.
Further information on these dampers and where they are designed to be used can be found in:
- EN 12101-8:2011
- EN 1366-10 A1: 2017
- Smoke Control Damper by Paul White