Test facilities

When conducting smoke extraction tests the fire simulation method must be able to simulate the characteristic properties of a real fire. However, the realistic simulation of the plume is of essential importance.

Hot fire gases rising from the fire source form a highly turbulent convective flow in form of a plume. Ambient air is mixed constantly at the borders of the jet into the fire gas. The generated smoke gas mass flow depends from the fire intensity, the turbulence intensity in the plume and the height and the circumference of the plume up to the smoke gas layer. The fire intensity results from the thermal power per area, the so called specific heat release rate (DIN 18232-2) and the increasing fire area and the extent, respectively, of the fire development.

Real fire simulation of the plume only due to combustion cannot be used in rooms with relatively low ceilings and/or with temperature sensitive built in components under the ceiling. For theses applications I.F.I. developed a special smoke generator with equivalent heat release by adding light gases. The basic version generates an uplift of a fire of 0.5 MW heat release. Special spoilers provide the necessary lateral  turbulence and velocity distribution of the plume. The attainable heat release can be increased by adding further elements and the increase of the fire can be simulated due to the delayed activation of the different channels.

The visualisation of the fire gases and the smoke propagation in the plume as well as under the ceiling is achieved by adding fog generated by a harmless and non-polluting fog fluid.

When conducting smoke extraction tests the fire simulation method must be able to simulate the characteristic properties of a real fire. However, the realistic simulation of the plume is of essential importance.

Hot fire gases rising from the fire source form a highly turbulent convective flow in form of a plume. Ambient air is mixed constantly at the borders of the jet into the fire gas. The generated smoke gas mass flow depends from the fire intensity, the turbulence intensity in the plume and the height and the circumference of the plume up to the smoke gas layer. The fire intensity results from the thermal power per area, the so called specific heat release rate (DIN 18232-2) and the increasing fire area and the extent, respectively of the fire development.

Thermal and thus very realistic plume flows can be generated by the patented I.F.I. fire simulation device. This device is based on a gas burner technology and also shown as example in VDI 6019-1. The device consists of modular components to be positioned variably. The liquid gas burners are controllable independently. Thus, the development of the heat release rate and the propagation of the fire can be simulated as often as required under the same boundary conditions.

This procedure allows the quantitative and qualitative testing of functionality and efficiency of the measure for the discharge of smoke and separation (division) of smoke section, especially in large building, e.g. exhibition halls, atria, arenas and multi-storey halls. Configurations with 10 burners and a maximum heat release of 1.2 MW or with three large burners with a maximum heat release of in total 7.5 MW, respectively, can be used. For special fire scenarios other burner configurations can be provided by I.F.I. on request.

Also for thermal real fire tests special spoilers provide the necessary lateral turbulence and velocity distribution of the plume. The visualisation of the fire gases and the smoke propagation in the plume as well as under the ceiling is achieved by adding fog generated by a harmless and non-polluting fog fluid. For these tests four large smoke generators are used simultaneously. Due to the necessary amount of heating power  for the evaporation of the fog fluid during the tests each smoke generator requires an electric circuit of 230V and 16 A fuse protection.

Car fires show mainly flames coming out of the motor compartment and the passanger compartment. Therefore I.F.I. prepared a car body with 2 burners in the motor compartment and 4 burners in the passenger compartment together with fire protection equipment. The burners can be activated in staggered intervals according to data determined by real fire tests (spread of fire szenario, heat release curves). A thermal heat release up tp 8 MW is possible. The combustion of the liquid gas is residue-free, the smoke is made visible using fog and smoke particles, which provide a realistic haze of the air causing no health risk and not leaving critical residue in the tunnel, sport arena or fair hall.

The special fire simulation car is maily used for simulated fire tests with high thermal heat release at commissioning tests of tunnels.

For drills of  first-aiders and emergency service personnel the modelling of the thermal properties of a realistical fire and  a smoke free layer is not always necessary. For the drill purpose is it essential  to provide an as complete as possible smoke logging because this simulates the worst case and allows to test or to check the orientation or evacuation and communication among the personnel during the simulated fire brigade operation. 

Due to its expert knowledge in simulating smoke in real fire tests I.F.I. can fulfil these requirements with its large smoke generators. Example: A four lane highway tunnel is filled with smoke within minutes so that the emergency service personnel could start the drill with their technical equipment, e. g. infra-red camera, close to reality.

Please note: each smoke generator needs a 16A fused 230V-circuit because of the considerable heating power.

The aerodynamic free area of NSHEV has to be determined according to EN 12101-2 using full scale or model scale ventilators without and with simulated wind influence. The relevant test rigs for these measurements have been designed by I.F.I. A schematic of the test rig for model scale investigations (typical scales 1:5 through 1:10) is shown below.

The scale model of  the NSHEV is mounted on a turntable integrated in the ceiling of the specially designed settling chamber. Due to the settling chamber arrangement the flow from a large room, i. e. without wall disturbances, is simulated. The open jet of the Large I.F.I. Industrial Aerodynamics Wind Tunnel is used for side-wind simulation. To increase the wind speed a smaller nozzle is fitted to the large nozzle.

The aerodynamic free area of NSHEV (= natural smoke and heat exhaust ventilators) has to be determined according to EN 12101-2 using full scale or model scale ventilators without and with simulated wind influence. The test rigs for these measurements have been designed by I.F.I. A schematic of the test rig for full scale tests is shown below.

The NSHEV is mounted on a turntable integrated in the ceiling of a specially designed settling chamber. Due to the settling chamber arrangement the flow from a large room, i. e. without wall distrubances, is simulated. The nozzle has a width of 4 m and a height of  2.5 m. The mean velocity in the nozzle cross section area is, in accordance to EN 12101-2, 10 m/s (= 36 km/h or wind force 5 of the Beaufort scale).

Figure below:
side view and top view of the test rig for the determination of the aerodynamic free area of NSHEV according to EN 12101-2.

Fume cupboards are furniture for laboratories working with chemical or biological substances. Due to an integrated exhaust system fume cupboards prevent propagation of possible pollution from the working area in the fume cupboard into the laboratory. 

Fume cupboards are tested in accordance with 
EN 14175-3:2003. These tests comprise the measurement of the volume flow of the fume cupboard, the face velocity into the working area, the tracer gas concentration in front of the fume cupboard and hence the containment as well as movements in front of the fume cupboards. Theses tests require as special test room.

This test room with the necessary ventilating system, measuring equipment and an automated device to simulate the movement of a laboratory technician in front of the fume cupboard is available at I.F.I.'s.

The I.F.I. Roof Tester has been designed for wind stability tests on roofing systems. It enables the realistic simulation of the wind gustiness with short time suctions of up to 10kPa. Roof systems of dimensions 6 m x 2,5 m may be tested. The test specimen, e.g. loosely laid and mechanically attached or adhesively attached membranes are subjected to wind load cycles typical for a 5 year return period. The failure load and the admissible system load are determined by increasing the load level in consecutive cycles. Typical failure modes observed on roofs, e.g. fatigue failures, may be realistically investigated with the I.F.I. roof tester.

Manufacturers may gain interesting findings about design loads and possible weak points deriving from the interaction of the elements and may take this as opportunity to improve their products.

Within the scope of a programme of work of the EOTA, guideline ETAG006 has been replaced by the European Assessment Document EAD 030351-00-0402 „ systems with mechanically fastened flexible roof waterproofing sheets “. In chapter 2.2.1.3 and in annex 1 this EAD document refers to EN 16002 determining the details of the test methods to be applied and we are glad that we can comprehensively map this guideline for the performance of the test runs.

In the following please find a short overview on the most significant data, adapted to EN 16002:

Width:                                  2,5 m

Test surface:                      15,0 m²

The Driving Rain Test Facility is used to investigated the water tightness of tiled roofs and shingled walls. The test specimen - width 2 m and length 3 m - will be covered by the tiles or shingles provided by the client. It is exposed to a combined rain and wind action. The pitch angle may be adjusted relative to the horinzontal axis of the wind tunnel.

Water penetration under a tiled surface is mainly due to the wind stagnation at the lower edges of the tiles. The corresponding stagnation pressure forces the water flowing down the tiles ord shingled surface into the batten space. The intensity of the rain and wind action may be quantified according to LACEY as driving rain index (DRI). The validity of the driving rain index has been developed by LACEY in the 1970ies and was confirmed by CHOI in Canada in the 1990ies.

The leakage of buildings and building components is a major source of energy losses, both heating energy during winter and cooling energy during summer. The air tightness of buildings is therefore a major influence for the decrease of energy consumption. I.F.I. may provide equipment for a standard blower door test or similar equipment adapted for special test demands.

ISO 9972 describes a test method to quantify the leakage of buildings or building components. The volume flow necessary to subject a room to a well defined pressure or suction will be measured. According to continuity equation this volume flow is equal to the leakage flow at the given pressure differential. It may be converted to specific parameters, e. g. air exchange rates.

For the uncomplicated and contactless recording of surface temperatures I.F.I. uses, if required,  a portable digital thermography camera. The thermography camera has been used e. g. for the detection of  structural physical defects in the insulation of an indoor ski slope or the heat release of a garbage incineration plant. When looking for such defects outside of the building appropriate weather condition are necessary.

The Large I.F.I. Industrial Wind Tunnel is situated in wind tunnel building in the main 
I.F.I. laboratory (Welkenrather Straße 120). Using the large nozzle (4 m width x 2.5 m height) the wind speed may be varied continuously up to a max. speed of  10 m/s. Using a smaller nozzle (dimension 2.25 m x 1.5 m)  the speed may be varied continuously 
up to 20 m/s.

A turntable of diameter 6.5 m is fitted downsream of the nozzle. The open jet test 
facility may be converted to a Eiffel-type, open jet wind tunnel giving a test section length of 10 m.

The Large I.F.I. Boundary Layer Wind Tunnel has a test section cross section area of 
2.7 m x 1.5 m. The wind speed above the boundary layer may be varied continuously up to a max. speed of  23 m/s. The atmospheric wind flow in the test section may be simulated  by using Counihan-turbulence generators and various surface roughness elements. The model scale of the wind flow is in the range of 1:150 through 1:500. Wind loads on buildings are determined according to the guidelines of the Wind Engineering Society (WTG) as recommended, e. g. in the German wind loading standard 
DIN 1055-4:2005-03.

A turntable of  2.5 m diameter is fitted in the test section. The measuring equipment includes a modern online pressure measuring system and a three-dimensional probe traversing mechanism.

The Small I.F.I. Boundary Layer Wind Tunnel has a test section cross section area of 1.78 m x 0.9 m; the wind speed above the boundary layer may be varied continuously up to a max speed of 25 m/s. The atmospheric wind flow may be simulated in the test section by using Counihan-turbulence generators and various surface roughness elements. The model scale of the wind flow is in the range of 1:250 through 1:800. Wind loads on buildings are determined according to the guidelines of the German Wind Engineering Society (WTG) as recommended e. g. in the German wind loading standard DIN 1055-4:2005-03.

A turntable of 1.5 m diameter is fitted in the test section. The measuring equipment includes a modern online pressure measuring system and a three-dimensional probe traversing mechanism. The wind tunnel is fitted with a special sand trap for sand erosion studies. A mirror fitted above the test section enables the monitoring and documentation of the surface flow field using the sand erosion technique without distortions.

Flow visualisation is an important method to investigate fluid flows. Water channels are a useful and simple tool for the study in particular of two-dimensional flow situations, e. g. flow around profiles or flow through louvers.

The flow in an open water channel is, when the relevant similarity laws are applied, equivalent to the two-dimensional flow through the object under study. Streamlines are usually made visible by applying appropriate particles to the water surface and using long-time exposure photography. Pressure differences, e. g. the pressure loss in louvers, may be obtained by measuring the difference in water height.

The emphasis of water channel studies is usually on a quick and simple flow investigation, e. g. to pinpoint areas of flow separation and to check the velocity distribution in critical cross sections. To avoid flow separation the geometric contours, e. g. of specially formed bends, may be quickly optimised. The I.F.I. water channel is an important tool for optimisation work in industrial aerodynamics and a lab tool of the Department of Aeronautics of the Aachen University of Applied Sciences.