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Evacuation Distances - Bombs
I have the following from some previous work:
100 metres (minimum). Letter/Briefcase
200 metres (minimum). Suitcase/Car
500 metres (minimum). Van/HGV vehicle
My concern is that I can't find any citing to these. Does anyone know where these original came from and have a link to the Govt et al. document? Or have these changed?
Andrew
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30 miles plus for one megaton thermonuclear....
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As an x-sapper I sent many a happy hour blowing things up and defusing things so my thoughts are these:
Distance etc. is all to do with what the bomb [no use of technical words here] is made up of so distance etc., unless you know the detail, is anybodies guess so I would not rely on such pieces of information as two identical suit cases may contain very different charges so each suitcase would have a completely different risk rating to the other
Of interest; why are U asking the question?
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Andrew
Been about 15 years since I had involvement with some evacuation procedures, but did use to work for an organisation that was potentially a political target, with other similar employers around us. We had talks with our local emergency services. They said they would tell us where they wanted us to evacuate to on any threat occasion. They said if we had a standard muster point as we did in our fire procedures we could actually be walking into the danger area.
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When I was in the TA (REME) I used to run as far as I could but that was PE4
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I recollect that generally the Fire Services stand by at 400 yds from the site.
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bob youel wrote:As an x-sapper I sent many a happy hour blowing things up and defusing things so my thoughts are these:
Distance etc. is all to do with what the bomb [no use of technical words here] is made up of so distance etc., unless you know the detail, is anybodies guess so I would not rely on such pieces of information as two identical suit cases may contain very different charges so each suitcase would have a completely different risk rating to the other
Of interest; why are U asking the question? And the terrain will make a difference to blast radius as well.
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bob youel wrote:As an x-sapper I sent many a happy hour blowing things up and defusing things so my thoughts are these:
Distance etc. is all to do with what the bomb [no use of technical words here] is made up of so distance etc., unless you know the detail, is anybodies guess so I would not rely on such pieces of information as two identical suit cases may contain very different charges so each suitcase would have a completely different risk rating to the other
Of interest; why are U asking the question? Been looking at Bomb Procedures and where I see "facts" I like to ensure that I can cite back to primary sources. All I appear to get re. this distances is lots of organizational procedual documents which have these (or similar) but no actual source.
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Looking at http://www.cabinetoffice...nse-Recovery-24-7-12.pdf I can see that it refers to "appropriate distance" but not the magic numbers I keep finding in organizations bomb evac procedures. This is curious. So far its appear more like a collective belief in numbers which appear to have no evidenced foundation.
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In the website referred to by John J, which is the USA one, it clearly states that "this table is for general emergency planning only. A given building's vulnerability to explosions depends on its construction and composition. The data in these tables may not accurately reflect these variables. Some risk will remain for any persons closer than the Outdoor Evacuation Distance"
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jay wrote:In the website referred to by John J, which is the USA one, it clearly states that "this table is for general emergency planning only. A given building's vulnerability to explosions depends on its construction and composition. The data in these tables may not accurately reflect these variables. Some risk will remain for any persons closer than the Outdoor Evacuation Distance" Sorry. I should have acknowledged the US source. Naturally, given that a UK response plan would work within a framework of advice provide by similiar UK Govt documents I was trying to find the one which provides similiar data tables. I don't mind using that table, but is seems a bit odd that the National Counterterrorism Center is providing something like this, but nothing I can find within UK or EU sites. Also thanks to John J re. this document as it the table is great. B
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I went on an Incident Control Officer (ICO) course last year, and the tutor said that he heard that the distances used are based on the distance used during WWII when dealing with unexploded German bombs! In other words they were not scientific at all but based on a sort of rule of thumb. If you think about it, and some respondents have alluded to this, that the radius of possible damage is very variable depending on, the type of explosive used, what it is in( rigid container, loose pack etc), was it out in the open or in a building, does the building have glass or masonry walls, is the terrain flat etc . Even the wind direction or air humidity can have an effect. If there is a creditable bomb threat, we have been told to get completely off site; not the car parks, but off-site completely. This is both to protect our staff from the risk of the bomb but also to make the work of the security services easier as they won’t have any civilians getting in the way.
I am going on a refresher ICO course in April, and I’ll ask more questions then.
The Counter Terrorism Specialists with your local police force should be able to give you more specific advice.
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The USA NTCT Bomb Threat Stand-Off Distances Table, as per the footnotes categorically states that:-
Explosives Capacity (TNT Equivalent) is based on "maximum volume or weight of explosive (TNT equivalent) that could reasonably fit in a suitcase or vehicle."
Mandatory Evacuation Distance is "governed by the ability of typical US commercial construction to resist severe damage or collapse following a blast. Performances can vary significantly, however, and buildings should be analyzed by qualified parties when possible."
Preferred Evacuation Distance is "governed by the greater of fragment throw distance or glass breakage/falling glass hazard distance. Note that pipe and briefcase bombs assume cased charges that throw fragments farther than vehicle bombs."
I very much doubt that the above is based on WW II data, but you could try to contact NTCT for the basis of their data.
For their "Mandatory Evacuation Distance", they clearly state that ".................. Performances can vary significantly, however, and buildings should be analyzed by qualified parties when possible."
Ideally,
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Obviously, for any bomb threat, it will ultimately be the police etc who will ultimately decide the actual evacuation distance etc, but organisations need to have planning in advance, and the tables may be of some use.
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Andrew
Having lived and worked in N Ireland for half a century I can tell you that you will not find any definitive safe distances. Over many years I have worked with the PSNI on protection of critical infrastructure as my main background is the power industry. The PSNI provided plenty of advice on security, including "incident" response but would never commit on safe distances. Lately we have just finished a €600M interconnector between Ireland and UK and we have 2 key assets (converter stations), one in UK one in Ireland. Recent discussions with specialist units within the Police on both sides also failed to obtain a definitive distance(s) relating to bomb threat!
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I have researched authoritative sources of information for our emergency scenario planning that not only includes bomb threats, but also chemical incidents on site, such as a tanker or a lorry delivering chemiacls etc . Unfortunately, there does not seem to be UK sources. For chemicals the US source that I felt was useful was http://phmsa.dot.gov/sta...Files/Hazmat/ERG2012.pdfAn very good UK website is the The Centre for the Protection of National Infrastructure (CPNI) whose role is to protect national security by providing protective security advice. Protective security is 'putting in place, or building into design, security measures or protocols such that threats may be deterred, detected, or the consequences of an attack minimised'. http://www.cpni.gov.uk/
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Interestingly when taking 20 kg TNT equivalent in a brief case the calculated distance to 0.02 bar is 100 metres
Impulse 8.6 Pa s
Duration 6.9 ms
Arrival time of 98.5 ms.
Distance stated in previous document based on 100 kg TNT equivalent in a car, also results in 0.02 bar.
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jay wrote:The USA NTCT Bomb Threat Stand-Off Distances Table, as per the footnotes categorically states that:-
Mandatory Evacuation Distance is "governed by the ability of typical US commercial construction to resist severe damage or collapse following a blast. Performances can vary significantly, however, and buildings should be analyzed by qualified parties when possible."
Call me picky, but shouldn't the Mandatory Evacuation Distance consider the resilience of people rather than commercial buildings? I've only been caught in 2 bomb incidents, one live and one a false alarm. On evacuation, people were pushed back by the Police to stand gawping from 'a place of safety' behind a flimsy 3" wide piece of Police Line, Do Not Cross tape strung across the road! I'm still not sure how that tape was going to protect me, but since the buildings around were going to be OK perhaps I need not have worried
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Rule of thumb TNT equivalency in PIED and VIED's
Package 1 kg TNT
Case 20 kg
Car 100 kg
Van 500 kg
Truck 1000 kg
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Safe No Harm distance to personnel is 0.021 bar
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bob youel wrote:As an x-sapper I sent many a happy hour blowing things up and defusing things so my thoughts are these:
Distance etc. is all to do with what the bomb [no use of technical words here] is made up of so distance etc., unless you know the detail, is anybodies guess so I would not rely on such pieces of information as two identical suit cases may contain very different charges so each suitcase would have a completely different risk rating to the other
Of interest; why are U asking the question? Taking the briefcase IED scenario and considering various explosives i.e. TNT, Torpex, Semptex 1A and C4. The distances to (no harm) 0.021 bar are calculated as: TNT 100 metre Torpex 240 metre Semptex 1A 210 metre C4 225 metre. Probably best to base cordon distance based on Torpex in all cases.
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240 metres....
That's not an evacuation distance, that's nigh on a marathon distance!
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Some great advice here and it goes to show how little people may know as explosives alone without any added projectiles have an extensive human body damage range - my experience is from the late 60's to the early 70's and explosives have gotten more powerful over the years since then by my respect has not decreased
I think that today we suffer from the telly, movies and electronic games syndrome where the hero runs thought all types of 'bombs' going off around them without damage to their body and many many people believe that is how it is where the reality is very very different and 240metre is nothing if it is your/your loved ones life at risk
Police: I was in a situation only 16 years ago where the police were stood only two body lengths away from a suspicious suitcase luckily the bomb disposal boys turned up and sorted out what could have been a real mess
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Also, as this comes under Risk Preparedness, have a secondary safety zone - 500 meters from your site, preferably with a hard wall (T walls) around it.
When I worked for a company in Iraq, we had prefabricated concrete bomb shelters at various distances around our sites, but for staged evacuations we used a large concrete bomb proof aircraft hangar, that was about 1 kilometre from our site.
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OK - So I have honestly just checked a few things - no, it's not April 1st, this is the UK and this is an Occupational Health and Safety forum!
Not knocking the thread as the OP has asked a genuine question but hey, I don't think I'll get prefabricated concrete bombshelters passed through on this round of CapEx negotiations and my revenue budget just about covers PPE, a few signs and some glasses for the screen stairers.
When all the COSHH, PUWER, DSEAR, DSE etc etc stuff is ALARP then I'll take the safe distance I need to be from different types of explosives seriously as an OHSE professional - until then it can sit in with the airplanes falling from the sky and the other Business Continuity issues that effect insurance premiums to the tune of 50p per annum.
I am genuinely interested though (seriously) as you just never know when you will need this sort of knowledge and I'm all for life long learning.
I do so hope it comes up on Pointless this evening or Eggheads.
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I did the bomb evacuation routes and plans for a number of police stations, it is not just distance that is important, line of sight, terrain to be covered as well as risk of glass and projectiles also affect.
I will try and find out what I based my distances on and feedback but I think your search for an magic/rule number may be futile, too many variables.
Des
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Just to stick my oar in, and it's a few years since I was involved in this stuff, but think security etc in a military environment; safe distances are part of the control, equally important is getting people to OPEN windows and doors as they leave if a bomb is suspected. Sounds daft but leaving doors and windows closed will actually result in more shrapnel in the form of door splinters and shards of ballistic glass - open the doors and windows and the pressure wave is released / reduced faster with a lower peak value, and the effected area is reduced
Jim
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One of the other hats that I wear is that of "Security Manager". As a DfT "Known Consignor" all personnel who have access to or pack identifiable air cargo must undergo Air Cargo Security training, which is refreshed every 2 years, (essentially the same training that the security staff searching/x-raying hand luggage in the airports go through).
I last went through this training about 18 months ago, where the guidance on bomb threats was :-
- dial 999
- don't use fire alarm to initiate the evacuation
- don't use the normal assembly point, (secondary device might be placed there)
- based on the information available, identify a suitable intermediate assembly point 200m away (ideally in an open space and not in a car park)
- issue verbal instructions to evacuate to this point, use a tannoy system if available
- conduct the roll call at the nominated assembly point
- once everyone is accounted for, move to an assembly point 1/2 mile away and wait for guidance from emergency services
This is built into our evacuation procedure, which covers fire, bomb threat, chemical incidents and other disasters.
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Perhaps if you assess your workplace to be at particular risk, it may be best to create a (or a number of) protected spaces within the building or site. Evacuating large numbers of staff into the open as a result of a general threat or one involving a device outside is not always best practice, neither is predetermining assembly points Have a look at the CPNI website (already mentioned by Jay above). I have had dealings with this organisation, including meetings with very capable advisers. Although they do not aim to assist all businesses - just places described as 'critical national infrastructure' - the website has a great deal of information. http://www.cpni.gov.uk/S...lan/Evacuation-planning/
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