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Trial adits, testing tunnels, experimental galleries

Premises of experimental galleries VVUÚ, a.s. Štramberk

The premises of experimental galleries VVUÚ, a.s. are situated in a former limestone pit on the outskirts of the town Štramberk (the upper part “Na Horečkách”). It is separated from the urban buildings by a series of terrain barriers. The galleries are digged into the extraction area of the Pit “Kotouč”.

This is a unique workplace in the Czech Republic that deals with the area of explosion protection and prevention, i.e. within research, testing and made-to-order activity.

There are altogether three experimental galleries. The great experimental gallery, with an arched profile of 9,2 m²and 300m in length. There is a parallel measuring gallery of the same length with a trapezial profile of 4,7 m². Both galleries are interconnected at their ends, which serves as a necessary way to release the explosion fumes.

The third, so called Old Gallery, digged in a right-angled profile of 5,5 m², locally adjusted for up to 20,6 m², is 56 m in length. The galleries are equipped with a dam chamber and anti-explosive dam objects to minimize transmission of undesirable explosion effects in relation to the external environment.

The great experimental gallery has 18 measuring points that are connected with a measuring gallery by drill holes. The distance between them is cca 15 m. The measuring points are made up of explosion-proof boxes that are let into side of the gallery. There is a possibility to attach two sensors to the box lid, either for pressure or flame, or combination of both. In specific cases, we are also ready to measure explosion temperatures. The cables from each box lead through the drill holes and pipelines over the measuring gallery to the distributing fields before the mouth of the gallery, there they are connected with a next cable track leading to a measuring object. There are other distributing fields in the measuring object by which the signals from the sensors are led into the individual channel on the measure devices. It enables variably to change the order of signals according to their number and measuring configuration.

There are altogether three measure devices. It is a PC with a measuring card DAQ Card-Al-16 XE-50 by National Instruments Co. (16 channels) and two transient memories “Adam” by Maurer Co., there is a maximum of 18 simultaneously measured channels.

The standard program of Testing Laboratory VVUÚ, a.s. for the experimental galleries represents accredited tests under the terms of work methods, i.e. tests on explosion-resistant dam objects, dam doors, hatch doors, dam air pipes and covers, passages for conveyor and dam ventilation grilles, resistant to pressure 0,5 or 1,0 MPa, including follow-up tests on device against explosion flame transmission, tests on closing mechanism of dam objects, tests on pressure resistance of doors, fire doors, fire doors and sheltered passages in building objects exposed to a defined explosion pressure up to 450 kPa, and tests on anti-explosion barriers.

We also meet requirements as specified in European standards ČSN EN 13124-1 Windows, doors and shutters – Explosion resistance – Test method – Part 1: Shock tube and ČSN EN 13541 Glass in building, Security glazing – Testing and classification of resistance against explosion pressure.

To extend frame of performed activities, the company above-standard program represents special testing upon the customer’s order, i.e. modeling of risk situations exposed to ignition of explosive atmosphere, work in the area of explosion and fire in enclosed area, explosion protection for specific installed conditions, assessment of explosion dynamic both dust-air and air-gas mixtures, in-put conditions, expansion, pressure progress, spreading velocity and its attenuation.

VVUÚ is the only workplace appointed by Czech Mining Office (ČBÚ) to approve materials for building anti-explosion closing and isolating dams, anchor elements of those dams and dam doors, air pipes, ventilation grilles, hatches and passages for conveyors. The tests in accordance with the approved methodology apply only to the experimental gallery “Štramberk.” This is also the only workplace for tests on efficiency of anti-explosion water and dust barriers. There is no substitution for performing the above mentioned tests.

Overview of performed tests on premises of experimental galleries in Štramberk

test on explosion resistance (reflex pressure 0,5 and 1,0 MPa)
test on efficiency of anti-explosion barriers
test on device against explosion flame transmission
test on closing mechanism of dam objects
test on pressure resistance (pressure resistance of doors, fire doors, fire doors and sheltered passages in building objects) exposed to a required explosion pressure (not accredited)

These tests have been accredited by ČIA (Czech Institute for Accreditation) and there are also obligatory work methods on the individual tests.