All BE Blast Valves with Prefilter are subjected to extensive testing during development, manufacturing and assembly, in order to ensure superior quality.

The following report is a summary of the basic perfotmance test each valve has to withstand. For additional data contact your local supplier.

The BE Performance Tests are executed in the factory's modern test laboratories as well as by the Standards Institution of Israel.

The BE Performance Tests are based on the Israeli and Swiss Standards as minimum requirements and in many cases exceed them. Beside the tests described herein, there are numerous other specific performance tests, in the scope of ensuring proper function of the valves in all extreme conditions.

The following tests are the most important test procedures, named "The Basic set" and include:

1. Pressure drop
2. Shut-off pressure
3. Closing-airflow
4. Blast Wave Durability
5. Closing time
6. Peak excess pressure
7. Impulse
8. Leakage
9. Dust feeding
10. Shock Durability
11. Coating
12. Thermal Resistivity

In the following pages we will present the test procedures and methods of measuring the "Basic set", according to the following scheme.

Each test procedure contains the following subparagraphs:

a) Definitions
- Background information on the necessity of the test
- Analysis of measurement and units

b) Passing criteria
- Required values supported by different National Standard Institutions (Israeli / Swiss Standard Institutions, DIN, ISO, etc.).
- BE applicable passing criteria for each test.

c) Test procedure
- Test description
- Test data

The BE-Blast Valves with Prefilters are designed to create a very low pressure drop, in order to ensure high system efficiency. A low pressure drop is especially important in manual operation.

The pressure drop is measured in Pa.

Israeli Standard:
All blast valves (3 bar protection grade) may have a pressure drop of 200 Pa. The valve is measured without prefilter.

Up to 300 m³/h ventilation airflow: The blast valve with the prefilter may have max. 300 Pa pressure drop after passing the dust feeding test.

More than 300 m³/h ventilation airflow: The blast valve with the prefilter may have max. 400 Pa pressure drop after passing the dust feeding test.

Swiss Standard:
Up to 300 m³/h ventilation airflow: The blast valve with the prefilter may have max. 300 Pa pressure drop after passing the dust feeding test.

More than 300 m³/h ventilation airflow: The blast valve with the airflow may have max. 400 Pa pressure drop after passing the dust feeding test.

BE Blast Valves with Prefilter are tested according to the Israeli and Swiss Regulations.

The airflow through the valve is measured by precise Venturi-Tubes and the differential pressure on the valve by wall pressure tapping manometers according to ISO 5167-1.

The shut-off pressure is the differential pressure (measured on the valve) at which it closes when overpressure or underpressure slowly increases.

The shut-off pressure must be low enough to pretect the shelter population from getting harm by the blast waves. It also should be high enough to keep the valve open while the ventilator is working.

The shut-off pressure is measured in Pa.

Israeli regulations for 3 bar valves:
Shut-off pressure for over and underpressure: Pschl < 10 kPa

Swiss regulations for 1 bar valves:
Shut-off pressure for over and underpressure: Pschl < 10 kPa

BE Blast Valves with Prefilter are tested for
shut-off pressure at overpressure and underpressure: Pschl < 10 kPa

The shut-off pressure is measured in the normal flow direction and also in the reverse flow direction.

The measurement is according to ISO 5167-1.

The closing-airflow is the maximum permitted airflow which causes the valve to close. The closing-airflow is measured in m³/h.

According to Israeli and Swiss regulations the 3 bar valve must close at max. 400% of the nominal airflow. According to Swiss regulations the 1 bar valve must close at maximum 300% of the nominal airflow.

BE 3 bar and 1 bar valves are checked to the corresponding level.

The airflow is measured with Venturi-Tubes, according to ISO 5167-1.

In order to protect the shelter-residents effectively from blast waves resulting from explosions, the valve must withstand several consecutive blast waves.

Israeli Regulations: The valve must withstand 4 blast waves at the side-on pressure of 3 bar. After these 4 blast waves the valve and the prefilter should not show any damage which may affect its proper function.

Swiss Regulations: The valve and the prefilter must withstand 4 blast waves at the side-on pressure of 1 bar, without causing damage that would affect its function. The pressure drop on the valve should not change by more than 20%.

BE Blast Valves with Prefilter are exposed to 6 standard blast waves (2 extra).

The valve is mounted on the BE shock tube and is exposed to the blast waves. Usually the pressure drop has changed 3 - 5 % after the 6 blast waves.

The pressure drop is measured according to ISO 5167-1.

The closing time (ts) is the time the valve takes to close under the influence of a blast-wave. The closing time has to be as short as possible in order to fully protect the shelter-occupants and all the equipment.

The closing time (ts) is measured from the moment the blast wave begins till the amplitude's firts zero crossing.

The closing time is measured in ms.

Israeli Regulations: Less than 4 ms for 3 bar valves

Swiss Regulations:  Less than 4 ms for 1 bar valves

BE Valves (1 and 3 bar) are tested to the above-listed vriteria.

For measuring the closing time the valve is mounted onto the BE shock tube and is exposed to the respective standard blast wave.

With the help of fast pressure transducers the closing time is indicated on the storage digital recorder and transmitted to the computer.

The peak excess pressure (Psp) is the maximum pressure that is measured behind the valve during its closing aciton.

The peak excess pressure is measured in kPa or bar.
100 kPa = 1 bar

For the 3 bar valve the peak excess pressure may reach 2.0 bar, according to Israeli Regulation.

For the 1 bar valve the peak excess pressure may reach 1.0 bar, according to Swiss Regulation.

BE Blast Valves with Prefilter (1 and 3 bar) are tested to the above-listed criteria.

For measuring of the peak excess pressure the valve is mounted onto the BE shock tube and is exposed to the respective standard blast wave. The peak excess pressure is sampled from the pressure transducer by a storage digital oscilloscope and transmitted to the computer.

The impulse ( I ) is the integral of the penetrating pressure / time gradient during the closing time of the valve. This is probably the most important indicator regarding the quality of a valve.

Both the Israeli and the Swiss Regulations allow an impulse of max. 150 Pa x s for all kids of valves.

BE Valves with Prefilter (1 and 3 bar) are tested to the above-listed criteria.

The Impulse ( I ) is calculated from the penetrating pressure measured behing the valve and the closing time.

For measuring the penetrating pressure and the closing time, the valves is exposed in the shock tube to the applicable standard blast waves.

Using very fast pressure-sensors the closing time and the pressure are transmitted through the storage oscilloscope to the computer for calculation.

Leakage is the air-volume that passes a valve that is being closed by a blast wave. The leakage is measured in m³/h or in % of the nominal airflow.

The Israeli and Swiss Regulations allow a leakage of 100% for all valves, i.e. the air-volume that may pass the valve during closing is equal to the valve's nominal airflow. BE Valves with Prefilter (1 and 3 bar) are tested to the above-listed criteria.

After exposure to standard blast wave the valve is closed. The pressure drop and the time during which this pressure drop occurs is measured. Using these two values the leakage is calculated.

To protect the shelter occupants from polluted air the prefilter has to arrest most of the incoming dust.

In filtration mode the prefilter protects the absolute filter from clogging. The prefilter's arrestance is verified by the dust feeding test.

The Israeli and Swiss Regulations demand, in accordance with ASHRAE-Standard 52.1 that:

- For every 100 m³/h airflow 20g ASHRAE Synthetic test dust has to be fed.
- The dust must be fed at a rate of approx. 70 mg/m³ airflow.
- The arrestance must be EU 3 (80 - 90%) according to EUROVENT 4/5

The BE Blast Valve with Prefilter (1 and 3 bar) are tested to the above-listed criteria.

The ASHRAE-dust is loaded with a dust-feeder according to ASHRAE 52.1. The arrestance of the prefilter is calculated by weighing it before and after the dust loading procedure. Afterwards "Measuring of the Pressure drop" (Paragraph 1) is repeated.

The valve has been designed to withstand all expected shocks and vibrations in a shelter. After withstanding a shock, there must not be any failure in operation.

Israeli Regulations for 3 bar valves:

max. velocity:             1.5 m/s
max. acceleration:       60 m/s²=6 g
number of shocks:       9

Swiss Regulations for 1 bar valves:

max. velocity:             0.63 m/s
max. acceleration:       63 m/s²=6.3 g
number of shocks:       6

The valve is mounted onto a shock-test machine in a position to simulate its typical mounting position in a shelter and is tested under the above-mentioned conditions. No effects on proper operation may appear.

In addition as an alternative test the valve is exposed to vibrations of 10 g for a duration of 60 sec.

No signs of damage may appear on the valve.

The coating must protect the valve sufficiently against corrosion, so as to ensure perfect functioning after storage for many years in possibly hot and damp shelters.

According to Swiss Regulations the coating of 1 bar valves must have a thickness of at least 60 µm. The parts that have been treated with surface coating must not show any signs of corrosion after stroge for a period of 2 weeks in a salt-water mist (3% NaCI-solution).

The cross cut test, according to ISO 2409, may not exceed class 2.

The BE valves are first phosphatized (1 µm) and then are protected with a 90 µm Polyester-Epoxy coating.

No signs of corrosion may appear after storage of 2 weeks in a salt-water mist. (A 5% NaCI-solution is used to simulate coastal environment.) The cross cut test is performed according to ISO 2409.

The valves may not be affected in their operation by thermal radiation.

According to Swiss Regulations all valves must be designed to withstand thermal waves of 200ºC with a duration of 5 sec.

According to Israeli Regulations the valves have to withstand a thermal test at 100ºC for a duration of 10 min.

The valve is placed for 10 min. into an oven at a temperature of 100ºC and then for 10 sec. at 200ºC. No signs of damage may appear upon it.