Linear Actuators

Linear actuators are predominantly used for sloping applications, where greater opening forces are required.  They can also be used on vertical vents where the vents are required to open to a distance greater than can be achieved by a chain actuator. They can be utilised to provide 90° opening if required.

Smoke Ventilation

Fire costs money. The cost as a consequence of fire, including property damage, human casualties and lost business, was estimated at £2.5 billion in the UK. If a fire does occur, then occupants must be protected.

SE Controls offers a comprehensive range of natural and powered Smoke Heat and Exhaust Ventilation systems (SHEV) suitable for any size and type of building.

Systems are designed to facilitate the safe escape of occupants in the event of a fire and to enable the fire to be fought in its early stages.

Natural Ventilation

Natural ventilation improves indoor environments, reduces CO2 emissions and is cost efficient.  Adaptive natural ventilation systems are less costly than traditional HVAC systems, being cheaper to install, run and maintain. With buildings currently consuming almost half of all commercial energy usage, producing 50% of carbon emissions, adaptive natural ventilation is leading the way for a sustainable future.

SE Controls are passionate about delivering energy efficient buildings with productive, healthy indoor environments; occupant productivity is significantly improved when thermal comfort and indoor air quality are optimised.

Window Automation

The use of actuators to automate windows can be used in both natural and smoke ventilation systems by reacting to sensors (rather than human response to stimuli) to control the level of comfort within an indoor environment, or to clear smoke to aid in the means of escape or firefighting operations. Automating a façade can also provide convenience for building occupants. Large heavy vents can be easily operated and held at various angles where appropriate to ensure the level of ventilation is sufficient.

Residential

In residential buildings it is likely that a fire would occur within an occupant’s apartment. During the occupants escape, it is probable that smoke would enter the common corridor or lobby. The smoke control system is designed to ventilate this smoke and to protect the common stair, to ensure safe occupant escape and clear access for the fire service.

Healthcare

Modern hospitals often utilise central atria to bring natural light into the building – and all the health benefits of additional daylight. The Atrium can be used to provide additional safety benefits of smoke ventilation and health benefits of natural ventilation.

Firefighting cores are used in tall buildings, buildings with deep basements, and buildings with large floor areas, to provide safe access for the fire service to enter the affected floor and act accordingly and require a form of smoke ventilation.

Commercial

Commercial buildings such as offices and retail buildings are typically designed with an Atrium to provide an attractive, naturally controlled light and airy space. Such spaces provide a significant challenge to the fire protection design teams due to typical heights being greater than 20m and due to the openness and ability of the fire to spread from floor to floor. Evacuation routes in these areas provide a significant concern, and can become venerable to the smoke spreading throughout the building, unless an effective smoke control system is implemented.

Educational

Education buildings are typically designed with an atrium in the main central spine of the building, to create natural light into surrounding classrooms and communal areas, to promote a productive learning environment for students.  Such spaces provide a significant challenge to the fire protection design teams due to the typical openness, height of the building and the ability for the smoke to spread from floor to floor. Evacuation routes for students and pupils in these areas provide a significant concern, unless an effective smoke control system is implemented.

What are the criteria that needs to be considered when choosing the correct actuator for your application?

1) Smoke or Natural –
This will govern what regulations product and certification will apply to the selection.
2) Chain or Linear Actuator
In general, chain drives tend to be used for vertical vents as they do not protrude within the room space, plus they can easily be powder coated to match the frames or concealed within the section.
3) Actuator size/ aesthetics
There is a huge variation in actuator sizes available but generally the size tends to increase proportionally with the stroke and opening force. Concealed actuators are possible but careful consideration must be made to maintain weathering and strength if sections require routing to accommodate the actuator.
4) Finish –
Most actuators have a standard finish grey or white powder coating or silver anodized. Alternative finishes are available but usually cost a premium and increase delivery time.
5) Voltage –
Most actuators are available in both 24v DC and 230v AC versions. Smoke ventilation predominantly utilises 24v DC that will operate via battery back up providing a secondary power supply. Natural ventilation uses both voltages although 24v actuators tend to be more cost effective and offer increased functionality.
6) Free are/ Opening stroke –
The free area requirement will govern the actuator selection and voltage.
7) Flex length and spec –
Standard flexes tend to be between one and three metres however extended flexes are possible up to a maximum of ten metres for DC actuators. If cables are run on or within the glazing system, we recommend 24v DC actuators for electrical safety compared to running 230v AC within a glazing system which is onerous to the fabricator.
8) Force (N) –
Actuators are measured in Newtons (9.81N = 1kg) Traditional force calculations for windows are based on butt hinges but many windows now utilise friction hinges which require greater force to close them especially when opened to the maximum possible angle as they lock out. The window also needs to be pulled up for the last ten degrees as they initially drop when they open on the stays. External elements such as snow load and wind load need to be factored into the force calculation. It is common for chain drives to lose force over their opening distance especially larger stroke actuators, so ensure sufficient force is provided throughout the stroke. The further the vents opens, the harder it becomes to push but the weaker the actuator becomes so be careful.
9) Locking points –
As most façade specifications are requesting high weather performance and vents are increasing in size, the need for multiple locking points on the vent is more prevalent. Whilst generally, leading edge widths above 1200mm tend to require multiple locking points, every system has its own criteria. Height is also a factor and automated multi-point locking solutions are now commonplace. Generally, the number of actuators (locking points) will mirror the test data for handles of the system company.
10) Hinge type –
The hinge type and relative path of the vent when opening is extremely important. Butt hinges provide a consistent opening path and weight to calculate the actuator type required. However, friction hinges produce and entirely different opening path and often the vent will drop initially. It is also common for friction hinged vents to lock close to the maximum opening distance resulting in the need for extremely strong actuators to close them again. Actuators that are fixed to the frame with a solid bracket will require pivot brackets when the radius of opening is too tight for the flexibility of the chain.
11) Vent position –
EN60335-2 requires automated vents below 2.5m from FFL to be risk assessed. The nature of the building and control strategy can negate the need for safety devices within the actuators or from separate devices such as infrared beams. Programmable features such as speed and closing force can be provided but this does not necessarily reduce the risk especially if the side of the vent is within the risk area due to the scissor effect.
12) Speed –
Smoke ventilators need to fully open within 60 seconds in accordance with EN12101-2. Chain actuator speed is important for accurate positioning in natural ventilation applications plus slower speeds provide greater protection against potential finger trap application.

Linear Actuators

Cruise Terminal

St. Edmund Campion School

Glass Casement Louvre

Fiegler Louvre

Jaguar Land Rover

Lion Match Factory

National Trust

Telescopic Spindle