Covers for BP-H Type Transformer Pits
For the covering of transformer pits, the BP-H sheet metal profile is advantageously used. It consists of a welded wire mesh filled with foam glass granulate. In the event of a fire, this granulate prevents the fire from spreading into the containment basin beneath the transformer and at the same time restricts the access of air to the pit.
Basic properties of foam glass granulate:
- non-combustibility
- environmental friendliness
- chemical resistance
- resistance to weather conditions
- very low bulk density
- long service life and thus stable value
| BP-H Sheet Metal Profile | |
| material | steel, hot-dip galvanized |
| length L | up to approx. 2500 mm |
| sheet thickness | 2 mm |
| module R | preferably n x 125 mm |
| width B | 150, 200, 300 mm |
| height H | 75 mm |
| edge fold T | approx. 10 mm |
Simple rules for designing transformer pit covers using BP-H fire-extinguishing profiles
BP-H profiles require support on only two sides, always at the ends. However, it is recommended that the bearing for BP-H profiles be provided around the entire perimeter of the pit to ensure better sealing of the basin. When designing the bearing width for BP-H profiles, the required clearances must be taken into account.
The clearance between the profile and the pit wall in the load-bearing direction should be at least 15 mm on each side; in the non-load-bearing direction, approx. 10 mm per each meter of width. The size of the clearances depends on the basin dimensions, the selected profile arrangement, and their length.
Regarding profile widths, it is advisable to cover the entire area using the standard production widths of 150, 200, and 300 mm, and to distribute any gaps evenly among the individual profiles. Regarding profile lengths, when designing a new transformer pit it is recommended to use a multiple of the grid module of 125 mm (this is the most cost-effective option). In the case of an already finished basin or during reconstruction, it is possible to add or subtract 1/4 to 1/2 of the grid module (a less advantageous option with additional costs). Non-standard lengths and widths can also be manufactured; however, this increases the price and extends the delivery time.
The maximum production length of BP-H profiles is approx. 2500 mm. For pedestrian loading, the clear span between supports must not exceed 1900 mm; see the load capacity table.
Attachments
Load capacity table for BP-H profiles (*.pdf )
BP-H leaflet (*.pdf )