22nd Aug 2021, 1:23 pm | #81 |
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Re: Bilsdale mast fire
An external drone survey is very likely to have been one of the first things done.
Internally, it's likely to be well-packed with all the feeders for all those antennae seen up the mast plus hanging stabiliser chains so not much room for flying. There's also the screening effect from GPS signals and the controller on the ground. Outside: Pretty certain Inside: not much of a chance David
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22nd Aug 2021, 1:57 pm | #82 |
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Re: Bilsdale mast fire
Arqiva are likely to proceed very cautiously with demolition after the (unrelated) 2016 Didcot A collapse, which killed 4 demolition contractors and injured many more. An investigation into the circumstances is still ongoing 5 years later.
https://en.wikipedia.org/wiki/Didcot...#2016_collapse |
22nd Aug 2021, 2:00 pm | #83 |
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Re: Bilsdale mast fire
I suppose you could drop a 360 degree video camera from the top with a parachute attached.
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22nd Aug 2021, 2:30 pm | #84 | |
Heptode
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Re: Bilsdale mast fire
Quote:
I see what you are getting at, but other pictures referenced here show the mast with paint simply peeling off it which might indicate a lack of general external maintenance. But of course getting up and down to apply a lick of paint routinely would likely be a ‘tall’ order! No doubt the constructional mast materials used are weather resistant (galvanised etc?) in themselves so just poor external cosmetics perhaps rather than fire/heat damage? Would not the feeder cables be specified as needing to be fire retardant or enclosed? Probably not an easy one to answer as that would be a very specialised job spec. If I were designing such a structure I think I would ensure the transmitter hall and associated high power (heat generating) equipment were quite physically separate from the mast for obvious reasons that we are perhaps witnessing here. I’m thinking of the general principle of fire barriers within more conventional structures and of course it may not be at all applicable in this industrial environment. As I say, just playing devils advocate and we will find all this out in due course. My money would be on the mast itself being ok apart from smoke damage but I know nothing. |
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22nd Aug 2021, 2:37 pm | #85 |
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Re: Bilsdale mast fire
I have no doubt one of the many coaxial feeders caught fire due to a poor junction somewhere causing arcing and ultimately fire. Once these things start there is no stopping them unless they have a fire retardent mix in the coax plastic sheath. Of course you would expect the transmitter to shut down if there was a high vswr caused by a faulty connector but often in the antenna a mismatch in a distribution system is not enough to trip the tx. I used to work in the high power broadcast antenna business and have seen it happen. Chris G0EYO (ex Eddystone, ex Marconi, ex Alan Dick & Co)
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22nd Aug 2021, 2:55 pm | #86 | |
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Re: Bilsdale mast fire
Quote:
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22nd Aug 2021, 3:06 pm | #87 |
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Re: Bilsdale mast fire
Much in these structures is counter-intuitive. Self-extinguishing or fireproof materials might not be required in a building with no normal human occupancy. The base is the most critical place, where stresses are greatest. The fire was already in the place you would most want to protect so there's not much point in trying to stop it moving further up.
Putting airtight/fireproof decks at intervals up it would have added a lot to the mass being supported and a stronger mast would have be needed, and the mast would have had to be even stronger still to support its own increased mass. You also need a clear, tall chamber to hold the sway damper chains, and with the heavier construction for fireproof decks, you need heavier chains. To understand sway dampers, read up on the John Hancock Building (still standing!) Boston USA. The same mechanism was implicated in the Emley Moor mast collapse. There are articles on Winter Hill about how it was updated with sway dampers to prevent it 'doing an Emley'. David
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22nd Aug 2021, 3:18 pm | #88 |
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Re: Bilsdale mast fire
Presumably a tubular mast functions as a pretty effective chimney once a fire is established at the bottom.
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22nd Aug 2021, 4:08 pm | #89 |
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Re: Bilsdale mast fire
That was my thinking, updraft can be ferocious and result in temperatures far beyond the same materials burning in the open. Fire-retardant materials get induced to burn by sufficiently intense initial sources and the retardants used can give rise to unpleasant and hazardous gases and residue.
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22nd Aug 2021, 4:17 pm | #90 |
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Re: Bilsdale mast fire
Reading through this thread It's a good job the experts are in charge of the job
Lawrence. |
22nd Aug 2021, 4:22 pm | #91 |
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Re: Bilsdale mast fire
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22nd Aug 2021, 6:11 pm | #92 | |
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Re: Bilsdale mast fire
Quote:
IMHO the mast is scrap! If I was Arqiva's risk-manager and given that they'll no doubt be facing penalty-clauses in their contract for failure-to-provide the contracted coverage to their clients I'd be giving the go-ahead to topple it as soon as possible [even dropping it into a SSSi and paying the likely £50K fine out of petty-cash - that's the sort of judgement-call risk-managers do on a daily basis] so site-clearance and rebuilding work can start at the earliest possible opportunity. |
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22nd Aug 2021, 6:14 pm | #93 |
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Re: Bilsdale mast fire
Definitely! Not only the 'experts' in mastage but the contracts-people who will no doubt be fretting over Arqiva's failure-to-deliver-the-contracted-service and the prospective multi-million-pound penalty-clause payments.
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22nd Aug 2021, 7:20 pm | #94 | |
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Re: Bilsdale mast fire
Quote:
Let's hold the speculation until some real facts emerge. David
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24th Aug 2021, 3:54 pm | #95 |
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Re: Bilsdale mast fire
Some more info from Arqiva, collected by dgicomp:
Updated 24/08/2021 - Delay to proposed temporary mast at Bilsdale Arqiva continues to do everything in its power to restore broadcast services as quickly and safely as possible following the fire which damaged the Bilsdale Mast earlier this month. The majority of homes affected, more than 400,000, have now had their TV services restored, and FM radio and Digital Radio have also returned to most households. Our teams are working round the clock, alongside our partners, to return services to normal for people across the area as quickly as possible. We fully recognise that, for those who remain affected, this is a frustrating time as services have not been restored as quickly as we had hoped. We apologise for that. The remaining stages of our plan require access to the original mast site to deliver materials, build and commission the temporary 80-metre mast which would expand TV services to the vast majority of households. The legal process to secure appropriate access to the site to build the temporary mast is taking longer than we initially anticipated and as a result it will not be operational by this weekend as we’d hoped. We are making representations to the court as to the severity and the urgency of the situation but we are in the hands of the judicial system currently. We continue to speak to the landowner to see if we can reach an access agreement whilst the application is being processed. We are doing everything we can to move this forward as quickly as possible and are seeking the assistance of everybody involved to accelerate the process. This definitely illuminates some of the stuff going on behind the scenes and shows that the timescales for the restoration of services are limited by red tape. David
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28th Aug 2021, 3:53 pm | #96 |
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Re: Bilsdale mast fire
Update via bobhowe:
update on Bilsdale mast fire from BBC News .TV licensing are offering a refund or free extension to there TV licence to cover the months affected . Mast operator Aqiva are in talks with the landowner to reach an agreement so it could put up a 260ft ( 80m ) tempory mast.
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8th Sep 2021, 10:02 pm | #97 |
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Re: Bilsdale mast fire
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10th Sep 2021, 10:22 pm | #98 |
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Re: Bilsdale mast fire
While the web page pointed to in the previous post says they'll have to see whether the mast can be reused or not, there was also an Arquiva post saying it would probably have to be replaced.
-Quote- Originally Posted by Arqiva 8/9/2021 Updated 08/09/2021 Arqiva’s Bilsdale Service Restoration Update – Arqiva Chief Executive to meet local leaders and community groups as latest new transmitter comes online at Sutton Bank – Around 500,000 households now returned to a Freeview coverage area – Arqiva will be meeting local organisations to discuss support for the most vulnerable affected North Yorkshire, UK, 08 September 2021: Arqiva, the leading UK communications infrastructure and media services provider, today provided an update on Bilsdale Mast following the recent fire that affected services across the region. Chief Executive Officer, Paul Donovan, will be meeting council and community leaders across the area to discuss the restoration of services and how to prioritise the most vulnerable people affected, and he returned to the site to view progress. A new, temporary mast has today restored some TV services to over 100,000 more people in North Yorkshire. While investigation into the cause of the fire continues, the implementation of the company’s recovery plans has now resulted in around 500,000 households being returned to a Freeview coverage area. Arqiva’s view is that the damage caused by the fire means it is probable that the existing mast will have to be dismantled. The company has used a combination of its existing sites and new, temporary structures to restore services and was today able to announce that an additional new transmitter site at Sutton Bank was now providing Freeview TV signals to over 100,000 households in areas including Harrogate, Knaresborough, Pickering, Ripon, Masham, Leyburn and northern parts of York. The next stage of the plan is to build an 80 metre-high temporary mast on land near the existing mast at Bilsdale. A team of around 100 people are in place to undertake the site preparation, helicopter lift for the mast structure and transmission set up. Working with local authorities, planning bodies, central Government, broadcast customers and regulators, the national park and others, good progress has been made in recent days. It is expected that this temporary mast will restore Freeview TV services to over 90% of affected households in the coming weeks. Speaking close to the damaged mast, and after meeting council leaders, Chief Executive Paul Donovan said: “First and foremost, I want to apologise again to those who people who have had their services disrupted by the fire at Bilsdale Mast; and especially to those who rely on television for companionship. “Our absolute priority is to restore services as quickly as we can. We have a detailed recovery plan which continues to progress as quickly as possible. This morning Freeview television services were restored for over 100,000 more homes in the region. “However, this is a complex task and there is clearly a lot more to do, so we are working with our partners as quickly and safely as possible. I would like to extend a special thank you to all those people who have been supporting friends and neighbours who may not have access to the internet or other sources of information and entertainment. We will prioritise the most vulnerable people affected. “Our teams are doing everything in their power to restore services for as many people as possible as quickly as we can and we will provide further updates on progress.” – Ends – So form your own opinion, place bets or just sit and wait. But the tubular masts have a poor history of resilience. Who'd be prepared to stick their head on a block by certifying it as safe? Safety is crucial. there will need to be people working in the transmitter buildings withing its fall zone. I don't hear any volunteers, so I'm expecting demolition. and the opportunity to be seized to put up a lattice tower or a mini-Emley to avoid invasive guy foundation changes around the immediate site. David (thanks to dglcomp for spotting the Arquiva release.)
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3rd Oct 2021, 10:00 am | #99 | |
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Re: Freesat Recorder box recommendations?
An interesting find, this recent BBC news article:-
https://www.bbc.co.uk/news/uk-england-tees-58766115 Contains the following statement... Quote:
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3rd Oct 2021, 11:34 am | #100 |
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Re: Bilsdale mast fire
As a reminder the news on this can be found here:
https://www.arqiva.com/news-views/ne...-bilsdale-mast Cheers Mike T
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