FAQ's
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General
The mild steel used for our standard, off the shelf, powder coated products are made from grade Q235 mild steel
Yes they can as long as they are separated by something
Download O&M Manual. Upon installation the vent should be manually checked by pushing on each blade to make sure it opens fully and closes completely. Once a year the vent should be visually checked to make sure there are no physical obstructions blocking the area surrounding the vent. After activation, the vent will self close and can be used again, no further maintenance is required.
Operates at 80 Pascals and fully open at 95 Pascals
The opening pressure of the standard SHX-UN can be adjusted to 45-50pas with the use of magnets.
No, the SHX-UN is 4 hour fire rated from outside to inside only
Yes, see install guide for details
The leakage is around 3% of the FVA:
SHX UN 300. 0.0023m2
SHX UN 500. 0.0063m2
SHX UN 700. 0.012lm2
SHX UN 1000. 0.038m2
If a complete seal is required our DWP, which fits with an SHX, can be supplied.
All pressure relief vents have some level of leakage. However, it is critical that there is no obstruction around the vent blades, allowing them to open at low pressure and, more importantly, close properly once the pressure subsides. This ensures that gas concentration is maintained.
No room has a complete seal and all rooms have leakage and the vent leakage is just added to the rooms natural leakage area. The key factor in an integrity test is whether the total leakage is low enough to maintain the required 10-minute hold time. If a room fails its integrity test, it is typically due to significantly larger hidden leaks, such as those found under floors and ceilings, rather than the minor tolerance gaps around a PRV’s blades.
If a completely airtight seal is required, we offer DWP units, which are single doors with foam seals, commonly used for external weather protection. These units are IP54 CAT II certified.
Yes, the SHX-UN can be adapted for ceiling and floor mounting for an additional cost, when requesting information for ceiling mounted units use the code SHX-UN CEI and for floor mounted units use the code SHX-UN FL
Yes, see install guide
To install in a plasterboard wall the cutout hole should be framed with the same type of studs used in the wall construction and then lined with the same plasterboard thickness and layers as the wall. This ensures that the hole in the wall maintains the same fire rating as the wall itself. The original SHX UN BRE fire test was conducted in a 2 hour plasterboard wall and achieved a 2 hour fire rating having followed this installation procedure.
The original 2 hour fire test was done on a plasterboard wall. It is 2 hours because it was tested it in a 2 hour fire rated wall and that's as long as the wall lasted. The SHX-UN will go on indefinitely
The High X-100 was renamed to SHX-UN in 2008 because the SHX UN is a High X-100 damper with wall liner and wall liner extension to fit walls from 0 to 380mm with no extra parts and therefore 'universal'. One of the points of the test is to show the hole made in a 2 hour plasterboard wall with one of our SHX UN or High X-100 dampers, it did not compromise the fire integrity of the wall. The wall failed after 2 hours but not around the hole cutout.
No, the SHX-UN is not smoke sealed but the DWP dynamic weather panel is smoke sealed and can be used with the SHX-UN.
From a vent point of view the SHX-UN will maintain integrity almost indefinitely but the fire rating of the wall will limit it. The basic rule of thumb is when you cut the hole in the wall for the vent, the cutout area needs to be constructed and finished as the wall is. e.g. If it were a plasterboard wall then you would line the hole with studding and cover it with the same type and thickness of plasterboard.
No, the SHX-UN is not IP rated. The HE-BP Heavy Duty Blast Panel is IP54 Cat certified and can be used with out without the SHX-UN.
The standard powder coated SHX-UN is made from grade Q235 mild steel
FIA Guidance:
The most favourable location for the vent is on an exterior wall of the building.
The vent should be located taking due account of the discharge nozzles and any objects both inside and outside the enclosure in the vicinity of the vent.
The vent should be located on an area of wall within the enclosure which is devoid of all services or other fixtures or fittings that could impede the flow path. Where available free wall space is limited, consideration may have to be given to having a bespoke vent manufactured which will fit the available space constraints.
Guidance on Venting of Gas Systems_Issue2The most significant hazard which arises from obstructions placed on either side of the vent are those which are of a non-fixed or temporary arrangement, which may impede flow or prevent the vent from functioning correctly.
Such items may not be present at the time at which the gaseous fire fighting system is designed and ultimately handed over; examples may include skips, packing boxes, filing cabinets etc.
Where obstruction of either side of the vent is possible, suitable warning notices or physical barriers should be provided.
The discharge of a gaseous fire fighting system causes rich streams of extinguishant to be liberated from the discharge nozzles, which dissipate the further the flow gets from the nozzle. It follows, therefore, that placing a vent in close proximity to nozzles and directly in the path of discharge may cause a disproportionate quantity of extinguishant to be vented during the discharge.
Vents should be positioned taking into account the above points and any location in the enclosure boundary maybe suitable.
Intumescent mastic was not used during the fire test because it doesn’t effect the integrity of the unit but its useful to use were the wall liner meets the vent to help reduce the leakage.
Typically, we would not recommend any obstruction in front of the vent. However, as a general rule, we usually say any obstruction in front of a vent should be no more than 50% of its size — so around 150 mm for a 300 mm vent, or 500 mm for a 1000 mm one.
The gap between the obstruction and the vent should allow the same free area as the vent itself.
Yes, the hole cut out sizes listed for the SHX-UN include 10mm of tolerance
If a stainless steel weather panel is required for an SHX-UN MOT installed on an external wall, the HE-BP or DWP can be used by installing a chain actuator on the panel so that you can motor open both units. The only issue there would be that the HE-BP or DWP would not automatically open just on air or blast pressure however you can just motor open the HEBP at the first stage of the alarm signal and then allow the SHX-UN MOT to just open and then close just from the gas suppression system discharge.
Download O&M Manual. Upon installation the vent should be manually checked by pushing on each blade to make sure it opens fully and closes completely. Once a year the vent should be visually checked to make sure there are no physical obstructions blocking the area surrounding the vent. After activation, the vent will self close and can be used again, no further maintenance is required.
No, the DUX is 4 hour fire rated from inside to outside only
Yes they can as long as they are separated by something but the recommended unit for two way venting if stacking is required is the DMX
The DUX is gravity and air pressure operated sono electrical motors. It is designed to open at 85 to 95 pascas for negative and around 100 to 120 pascals positive air pressure
Negative pressure relief means the gas protected room air will shrink due to the chilling effect of a halocarbon gas such as FM200 or NOVEC and so for this action the vent will open into the room. After a short period these gasses warm up and then create a positive pressure and for this action the vent will then open outwards from the room. This is if you are using a two way vent such as the DUX or DMX
The standard powder coated DUX is made from grade Q235 mild steel
FIA Guidance:
The most favourable location for the vent is on an exterior wall of the building.
The vent should be located taking due account of the discharge nozzles and any objects both inside and outside the enclosure in the vicinity of the vent.
The vent should be located on an area of wall within the enclosure which is devoid of all services or other fixtures or fittings that could impede the flow path. Where available free wall space is limited, consideration may have to be given to having a bespoke vent manufactured which will fit the available space constraints.
Guidance on Venting of Gas Systems_Issue2The most significant hazard which arises from obstructions placed on either side of the vent are those which are of a non-fixed or temporary arrangement, which may impede flow or prevent the vent from functioning correctly.
Such items may not be present at the time at which the gaseous fire fighting system is designed and ultimately handed over; examples may include skips, packing boxes, filing cabinets etc.
Where obstruction of either side of the vent is possible, suitable warning notices or physical barriers should be provided.
The discharge of a gaseous fire fighting system causes rich streams of extinguishant to be liberated from the discharge nozzles, which dissipate the further the flow gets from the nozzle. It follows, therefore, that placing a vent in close proximity to nozzles and directly in the path of discharge may cause a disproportionate quantity of extinguishant to be vented during the discharge.
Vents should be positioned taking into account the above points and any location in the enclosure boundary maybe suitable.
The DUX can be made to order in stainless steel but it is recommended to use the DMX 316L two way modular vent which is available off the shelf. Ratio below:
2xDMX300 for a DUX300
4xDMX500 for a DUX500
6xDMX500 for DUX700
13xDMX500 for DUX1000
You use the negative FVA to choose the vent. With Novec, the positive pressure is only about 10 to 20% of the negative so we don't look at the positive only what the negative FVA required is and supply a vent based on that.
A DWL or DWP can be used on their own for pressure relief if a fire rating is not required
Yes, the DWP can be used for pressure relief without the use of an SHX-UN as long as a fire rating is not required
The neatest 2 way vent to install in a door is the DMX. We make a small 60mm Z Frame to help with this
For chemical gasses, mounting at low level is preferable as the agents are heavier than air
Certification
The HE-BP heavy duty blast panel is IP54 Cat Certified.
European Union
Yes, customers purchasing goods from outside of the UK will be responsible for payment import duties and taxes. Due to new CBAM legislation, AFP are no longer able to offer DDP incoterms to Europe. CBAM requires companies to have an EU entity to report on CBAM and when AFP ships products DDP they automatically become an importer into the EU and are required to report on CBAM. This cannot be done without an EU entity.
There is no standard for pressure venting in the EU and therefore the products are out of scope and do not require CE marking. CE certificates apply to fire dampers, AFP do not supply fire dampers.
International Shipping
AFP can arrange shipping to European countries but do not arrange shipping to international countries outside of the UK and Europe. For shipping outside of the UK and Europe shipping terms are EXW customer collect only.
Most AFP standard off the shelf products have Chinese origin and therefore do not come with a certificate of origin as standard. A Chinese certificate of origin can be provided upon request for a cost of £100 and can take up to 10 working days to obtain.
We, AFP Air Tech Ltd, herewith confirm that our products:
- do not have their origin in Russia,
- were not exported from Russia,
- when manufactured outside Russia, do not incorporate Russia-originating iron
and steel products as covered by Annex XVII of the Regulation in any quantity, unless such products manufactured in third countries have been imported to the EU prior to September 30, 2023.
Policy Documents
We, AFP Air Tech Ltd, herewith confirm that our products:
- do not have their origin in Russia,
- were not exported from Russia,
- when manufactured outside Russia, do not incorporate Russia-originating iron
and steel products as covered by Annex XVII of the Regulation in any quantity, unless such products manufactured in third countries have been imported to the EU prior to September 30, 2023.
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