Deflection and Wind Speed Tests
Introduction
The purpose of this test is to demonstrate that the Pollite frangible approach lighting pole fulfills the deflection and wind speed requirements stipulated within the FAA Advisory Circular (AC No. 150/5345-45c) and the ICAO Aerodrome Design Manual, Part 6 Frangibility.
This test will follow the testing procedures and qualification requirements set out in the above mentioned documents.
Deflection Test
In the case of this test we need to demonstrate that when a load is applied to the pole and that load is the equivalent of a 12.5mm coating of ice on the pole and a 60mph wind speed against the pole that the deflection of the light beam at the top of the pole will be no more than +/- 2 degrees in the vertical axis and +/- 5 degrees in the horizontal.
Wind Speed Tests
We need to demonstrate in the wind speed tests that the pole structure will withstand a load equivalent of wind speeds of 75mph with 12.5mm of ice on its surface and also wind speeds of 100mph without the additional ice loading. In both cases the integrity of the structure of the pole and its fittings must remain intact.
Test Loading and Deflection Calculations required
The following loads have been determined.
- Deflection Test: Equivalent Load Required for the pull test is 0.84Kn in horizontal or 1.18Kn at a 45 degree angle
- Allowable Deflection: 279mm
- Wind Speed Test (75mph/12.5mm ice): Equivalent Load required for the pull test is 1.29Kn (129kg)
- Wind Speed Test (100mph): Equivalent Load required for the pull test is 2.21Kn (221kg)
TEST ACCEPTANCE
The Deflection Test will be successful if;
1. On application of the load equivalent to a 60mph wind speed with12.5mm of ice attached to the pole, deflection of the pole in the horizontal axis is 5 degrees or less and on the horizontal axis 2 degrees or less. Permanent deformation of pole is unacceptable.
The Wind speed Tests will be successful if;
1. On application of a load equivalent to a 75mph wind speed with 12.5mm of ice attached to the pole, the structural integrity of the pole remains sound and intact. Permanent deformation of pole is unacceptable.
2. On application of a load equivalent to a 100mph wind speed, the structural integrity of the pole remains sound and intact. Permanent deformation of pole is unacceptable.
Pollite Deflection and Wind Speed Test Results;
The deflection and wind speed tests on the Pollite approach poles were conducted as per the above test plan on 24th April 2008 in the presence of Intertek Etl Semko.
Deflection Test
1. As per the test procedure illustrated above without a force applied, the distance of the plumb bob to the centre of the pole was noted to be 170mm.
On applying a load of 1.18kN at a 45 degree angle from the top of the pole as per the test procedure a reading was taken for the distance between the centre of the pole and the plumb line. This distance was measured at 430mm.
The allowable deflection of 2 degrees equated to 279mm as per calculations attached.
Therefore the deflection in the pole when the correct load was applied came to 260mm (430mm-170mm) within the 2 degree (279mm) deflection tolerance as illustrated in ICAO Aerodrome Design Manual, Pt 6, Chpt 4.9.18.
As the maximum allowable deflection in the vertical is 2 degrees and the poles fulfilled this requirement it was deemed unnecessary to further test for a 5 degree deflection in the horizontal due to the structure of the cylindrical pole being entirely equal.
No permanent deformation of the pole was noted.
Wind Speed Test Results
1. 75mph Wind Speed with 12.5mm of ice attached.
As per the calculations illustrated in appendix 1 an equivalent load to the wind speed illustrated above, 1.29 kN (129kg) was applied at 5m from the base of the pole.
Actual load applied 131kg with no permanent or temporary deformation in the pole noted.
2. 100mph Wind Speed with no Ice.
As per the calculations illustrated in appendix 1 an equivalent load to the wind speed illustrated above, 2.21kN (221kg) was applied at 5m from the base of the pole.
Actual load applied 230kg with no permanent or temporary deformation in the pole noted.
Conclusion
As per the deflection and wind speed requirements stipulated within the FAA Advisory Circular (AC No. 150/5345-45c) and the ICAO Aerodrome Design Manual, Part 6 Frangibility the Pollite frangible poles tested complied with those requirements.
Full Test Plans and Reports are available upon request.
