Health & Safety
Openreach: Embargo Climbing Pole 5i & 6i
9 April 2014
BT Openreach has placed an immediate climbing embargo on Type 5i & 6i Poles pending pole test and have immediately placed them to the front of the pole test programme. This information will be briefed to Engineers by their line managers on 10 and 11 April 2014.
Type 5i & 6i poles were supplied to BT by a company known as Scanpole. They were supplied from approximately 2000 until approximately 2006. Records are incomplete but these dates are believed to be correct. During that period approximately 10k - 12k poles were supplied each year so some 60k - 70k are likely to be in the network.
Immediate Climing Embargo
The decay in these poles can be aggressive and they may potentially progress to failure in a shorter than expected timescale. There is a potential risk to the public and also to our climbers and they have therefore been placed immediately to the front of the pole test programme with an immediate climbing embargo on these poles pending pole test.
Openreach say that anecdotal evidence suggested there was a problem with these poles failing prematurely. The level of decay being reported was such that if left to follow the normal pole test schedule, there was the possibility of one or more of these poles collapsing at some point. This was complicated by the fact that the location of these poles had not been fully recorded on the pole recording database (Artisan).
Openreach say a detailed investigation was commissioned and this has just completed. A total of 364 poles were tested across the North East of England, Northern Ireland and the Midlands. These poles were given a full Stage 2 test including Resistograph tests below ground and 82 were identified as D for decay. Of these 82 poles, 18 were recovered to secure yards for further investigation. When recovered they were tested again with hammer, probe and Resistograph before being sectioned by chainsaw to examine the wood internally.
High Test Failure Rate
A failure rate due to decay in the field was measured at 22.5%. Given that these are 9 - 12 year old poles it would be expected to find a rate of less than 0.1% so this is some 200 times greater than the expected norm. When examined in the controlled environment this rate dropped to 12.4% which is still 120 times higher. The difference can be explained by misinterpretation of the Resistograph traces. When a pole is wet inside; and also if the wood is still quite young it is not unexpected to find a very low trace which can be mistaken for decay. A number of the remaining sectioned poles which Openreach did not consider D were wet inside and the poles were only 10 year old. Although these poles were not D, this wetness is a likely pre-cursor to premature decay. The 22.5% find rate therefore has credibility.