LA CATASTROFE DEL DEPOSITO DI BUNCEFIELD IN DATA 11 DICEMBRE 2005
CONSIDERAZIONI IN MERITO ALL’EPISODIO ED ALLA SUA
VALENZA URBANISTICA
Ing. Gian Carlo Bello CVR Regione Lombardia
DESCRIZIONE DEL DEPOSITO
With its close proximity to the M1 motorway, the Buncefield oil depot has become one of the UK's major distribution terminals.
Reported to have a storage capacity of 150,000 tonnes, Buncefield holds stocks of not only oil and petrol but also the aviation fuel kerosene, used to supply airports across the region including Heathrow and Luton just 10 miles away.
The depot itself first came into use in 1968 but for the last 15 years has been run as a joint venture by oil giants Total and Texaco. It is also used by the other leading petrol firms BP and Shell.
The depot is in operation 24 hours a day, with 400 tankers being filled at the site every day from a total of 26 storage tanks.
A high-pressure oil pipeline, run by British Pipeline, runs all the way from the Lindsey oil refinery in north Lincolnshire to the Buncefield site, where the oil is then stored.
It is one of three underground supply pipelines feeding Buncefield.
TotalFinaElf operate within the UK two pipelines, transporting a wide range of petroleum products around the United Kingdom to all our customers.
The two pipelines are:
Fina-Line - a 10” multi-product high-pressure pipeline.
Colnbrook-Line - a 12” single product medium pressure pipeline.
The Fina-Line is a high-pressure fuels pipeline transporting products from
Lindsey Oil Refinery, North Lincolnshire to Buncefield Terminal at Hemel Hempstead.
Fina-Line transports products including petrol, diesel, aviation, agricultural and heating fuels, 24 hours a day, 365 days of the year to the Buncefield Terminal at
Hemel Hempstead, from where it is distributed to industry and community.
The Colnbrook Pipeline is a medium
pressure pipeline transporting aviation fuel from Colnbrook Rail Terminal into
Heathrow Airport.
The pipeline is a 12” diameter of welded steel construction and has been installed to a minimum depth of 1 metre cover.
What caused Europe's biggest blaze?
· Police keep open mind as investigation begins
· No indication of terrorist involvement in blast
Patrick Barkham
Monday December 12, 2005 The Guardian
There were several theories last night about the cause of the
Buncefield oil depot explosion. We examine some of them below:
Accident
The safety record at Buncefield and the 50 other major oil and fuel storage depots across the country is good, according to the Health and Safety Executive. In general, oil refineries are far more hazardous than storage depots. According to Total UK, there has never been a serious fire incident at the depot since it began operations in 1968.
Arson
Buncefield is staffed 24 hours and all visitors are required to identify themselves and sign in at the base. The 100-acre site is surrounded by
security fences and CCTV. However, security may not be flawless: one tanker driver at the depot at the time of the explosion described fleeing the scene by scrambling through "holes" in fences. Police did not signal they were seriously investigating arson as the cause.
Pipeline malfunction
Four major supply pipelines carry fuels into Buncefield. They brought 2.37m tonnes of fuel through the depot in 2002. All pipelines were shut down immediately after the explosion to stop even more fuel fanning the flames.
Pipelines are built to withstand direct impacts and industry experts said it was unlikely that the pipelines would be badly affected by the fire.
Human error
Buncefield does not achieve the highest level of safety under the International Small Site Safety Rating System but does rank at level 3, one below the highest rating. On a normal working day, there would be nine staff working
there. But early yesterday there were just two staff on site.
Storage tank failure
All the tanks at Buncefield are surrounded by bunding with the capacity to hold the full volume of any tank in the event of spillages. One eyewitness reported seeing smoke rolling off several of the tanks. The electricity on the site also
went down and alarms sounded before the explosion.
Plane crash
There were rumours early yesterday that a light aircraft had crashed into the fuel storage tanks at the depot. Some residents
reported hearing an aircraft flying overhead shortly before the explosions and Luton airport is nearby. Police later said no plane
had been involved in causing the explosion.
Terrorist strike
Militant Islamists were urged last week to attack oil installations in Muslim countries by Ayman al-Zawahiri, al-Qaida's deputy leader.
Police would not rule out the blast being a planned act but a terrorist strike was judged highly unlikely by security sources and
terrorism experts. There were no suggestions from any of the security services that investigators had evidence pointing to a terrorist act but an information blackout might be a police tactic if
detectives did not want to alarm the public. The timing of the explosion led experts to believe it was not a terrorist strike. The
fact the first blast happened early on Sunday meant it caused minimum damage.
Buncefield
Storage and Distribution, Oil Terminal
Existing hazardous development will constrain further development (see Policy 125). A 190 m consultation zone applies. Safeguard Scheme T7 (North East Hemel
Hempstead relief road) and Scheme Tv (Buncefield Lane cycleway) and its environment: see Schedule of Transport Proposal Sites and Schemes.
DACORUM BOROUGH LOCAL PLAN 1991-2011
Adopted April 2004
Proposals Map Sheets 1 - 5
Decreto Ministeriale del 20/10/1998
5.1.2 Procedura di valutazione
Tabella 2 – valutazione effetti Classe sostanza = 1 (benzina) Quantità > 10000 t
Categoria effetti = C
Distanza standard = 50 – 100 m
NOTIZIE DALLA STAMPA INGLESE
The force of the blast - which was heard up to 40 miles away - sent flames shooting 200ft into the sky.
"We ran out of the house just as the police were arriving on the scene - we could see the flames shooting up to 100 to 200ft in the air.
Serbatoi da 12000 m3, diametro circa 32 m.
Altezza fiamme circa 1.5 d = 48 m, cioè circa 150 ft On Sunday, firefighters worked to contain the fire, using a "curtain of water" between the flames and the remaining unexploded fuel tanks.
Seven out of more than 20 tanks remained intact.
Each was said to hold three million gallons of fuel.
(circa 12000 m3)
Quindi, la quantità coinvolta è stata circa 13*12000=
150000 m3 di prodotto
Una persona a 200 m ha avuto gravi danni polmonari Vetri rotti fino a circa 4 km
Rumore esplosione udito fino a circa 40 km
La massa di idrocarburi nella nube (UVCE) era di circa 1000 t ! La massa rilasciata era probabilmente l’intero contenuto di un serbatoio o la portata della pipeline per un tempo molto lungo.
DA INVESTIGARE
Se nella UVCE sono state coinvolte 1000 t di HC in fase vapore, di quanto è stato il rilascio in fase liquida ?
10000 t, 20000 t ?
La temperatura ambiente era molto bassa (< = 0 °C); come ha fatto a vaporizzare una massa così enorme di Kerosene Avio ?
Prodotto caldo ?
Mescolato con vapore d’acqua (riscaldamento) ? Boilover ?
Perché l’incendio si è esteso rapidamente all’intero deposito ? Dreni dei bacini aperti ?
Antincendio distrutto dalla prima UVCE ?
Effetti domino, per distanze di separazione inadeguate ?
Dove era il personale di servizio (2 persone in turno) ? I sensori di gas non hanno dato l’allarme ?
Per quanto tempo la pipeline ha continuato a pompare ?
