Editing Piper Alpha (section)

==Construction and layout==
[[File:Piper (west).png|thumb|400x400px|Simplified elevation view (platform west) of Piper Alpha]]
Piper Alpha's production facilities were designed by [[Bechtel]] in [[London]].<ref>{{Cite news |last=Barnes |first=Hugh |date=8 July 1988 |title=What Caused Piper Alpha to Blow Itself Apart? |work=[[The Herald (Glasgow)|Glasgow Herald]] |pages=15 |volume=206th year |issue=141 |issn=0965-9439}}</ref> The supporting platform jacket, as well as the [[Topsides|topside]] module structures and buildings, were designed by [[McDermott International|McDermott Hudson]].<ref>{{Cite journal |date=1980 |title=Discussion – Installation of the Piled Foundations and Production Modules on Occidental's Piper A Platform by S. Duvivier & P.L. Henstock |journal=[[Proceedings of the Institution of Civil Engineers: Part 1]] |volume=68 |issue=2 |pages=281–295 |doi=10.1680/iicep.1980.2408 |issn=0307-8353 |eissn=2054-0515}}</ref> The eight-legged jacket structure was constructed by [[McDermott International|J. Ray McDermott]] in [[Ardersier]], [[Inverness-shire]], and [[Union Industrielle d'Entreprise|Union Industrielle et d'Entreprise]] in [[Le Havre]], France, with the sections united in Ardersier before being towed out during 1975.<ref>{{Cite news |date=23 May 1974 |title=Oil Firm May Take Gamble |volume=192nd year |pages=3 |work=[[The Herald (Glasgow)|Glasgow Herald]] |issue=100}}</ref>{{sfnp |Matsen|2011|loc=chapter 1}} The jacket weighed around 14,000&nbsp;tonnes and was {{Convert|165|m|ft}} tall, of which a length of {{Convert|144.5|m|ft}} was permanently submerged. Four clusters of [[Deep foundation|foundation piles]] extended a further {{Convert|115.8|m|ft}} below the seabed. Topside modules weighing about 10,000&nbsp;tonnes in aggregate were lifted from a [[Crane vessel#Crane ships|crane ship]] and installed over the jacket in late 1976.<ref>{{Cite journal |last1=Duvivier |first1=S. |last2=Henstock |first2=P.L. |date=1979 |title=Installation of the Piled Foundations and Production Modules on Occidental's Piper A Platform |journal=[[Proceedings of the Institution of Civil Engineers: Part 1]] |volume=66 |issue=3 |pages=407–436 |doi=10.1680/iicep.1979.2827 |issn=0307-8353 |eissn=2054-0515}}</ref>

Piper's hydrocarbon facilities and principal utilities were distributed in four main modules (A, B, C, and D) separated by firewalls and sitting atop the steel jacket. Above the main modules were a [[Derrick#Oil derrick|drilling derrick]], various utilities, the living quarters, [[Gas flare|flare booms]], two [[Crane (machine)#Deck|pedestal cranes]], and the [[Helipad|helideck]].{{sfnp |Lord Caplan|1997|loc=vol. 1, section 2.3}}{{sfnp|Mannan|2012|p=2851|}}

For safety reasons, the modules were organized so that the most dangerous platform operations took place far from the personnel areas.<ref name=":26" /> However, the conversion from oil to gas broke this safety concept, with the result that sensitive areas were brought together; for example, the gas compression module was next to the control room. The close position of these two areas played a significant role in the accident.<ref name=":28">{{Cite episode |title=Spiral to Disaster |series=Disaster |network=[[BBC]] |date=9 January 1997 |season=1 |number=1 |last=Higgins |first=Bryn}}</ref>

The hydrocarbon inventory actually held within the platform was small in comparison with that contained in the pipelines, standing at around 80&nbsp;tonnes of process fluids and 160&nbsp;tonnes of [[diesel fuel]] (which was stored in tanks located above module C).<ref name=":26" />