Blast Proof Modulars in Chemical Plants

[StephenPL]

Does anyone have experience with putting blast proof modular buildings in petro-chemical plants on a permanent basis for operator shelters or on a temporary basis during maintenance as permit shacks?

 

[JLSeagull]

I don't know of blast-proof buildings. However we are using pre-cast concrete buildings for some analyzer shelters.

 

[pennpiper]

This is just my opinion.

There is no such thing as a "Blast Proof" building.
There are some "Blast Resistant" buildings, however, I think "Blast Resistance" is a relative term. You could bury the building under ground and a Bunker Buster would still spoil your whole day.
The BP oil company found out that it is not a smart idea to place temporary buildings in an operating refinery during maintenance as offices, permit shacks or contractor conference rooms.
Keep occupied buildings out of operation units.

 

[JLSeagull]

API RP 2FB provides some guidelines.

 

[dcasto]

Here Here pennpiper. Other companies have buildings 50% under ground and have large overhangs to try to keep flying debris from entering windows. I've even seen some with double air lock doors that weight a thousand pounds. Like all buildings, homes, offices, realestate, and farms the key is: LOCATION, LOCATION, LOCATION. A control room on the gulf coast was designed for 3 psi over pressure, but not for the falling steel that collapsed the roof.

 

[pennpiper]

I found this via google and thought I would share it.

Blast Resistant Structure
Protect employees today: Blast
resistant structures from Clegg Ind
cleggind.com



U.S. CHEMICAL SAFETY AND HAZARD
INVESTIGATION BOARD
Urgent Recommendation

Whereas:

1. On March 23, 2005, the BP Texas City refinery experienced a severe explosion
and fire accident involving a raffinate splitter tower within the isomerization
(isom) unit and associated blowdown system that resulted in 15 deaths, 170
injuries, and significant economic losses; the accident was one of the most serious
U.S. workplace disasters of the past two decades.

2. All of the fatalities and many of the serious injuries occurred in or around the nine
contractor trailers that were sited near process areas and as close as 121 feet from
the isom unit. This unit contained large quantities of flammable hydrocarbons
and had a history of releases, fires, and other safety incidents over the previous
two decades.

3. Workers in adjacent units were injured in trailers as far as 480 feet from the isom
blowdown drum. A number of trailers as far as 600 feet from the blowdown drum
were heavily damaged.


4. At the Texas City refinery, trailers had been periodically sited in and around
hazardous process areas for reasons of convenience such as ready access to work
areas. The trailers did not need to be located as close as they were to the process
areas in order for workers to perform their job duties.


5. Trailers had been sited periodically in the same location near the isomerization
unit for a number of years. On September 1, 2004, and prior to a safety
assessment, BP placed the trailer where 12 workers died near the isomerization
unit; a month later BP applied a siting policy to approve the location. The eight
other trailers placed nearby were not analyzed for hazards related to their location,
nor was the impact of the total occupancy of multiple trailers in close proximity
considered.


6. Under BP’s siting policy, trailers used for short periods of time such as
turnaround trailers were considered as posing little or no danger to occupants.
This approach conforms with the guidance provided in American Petroleum
Institute (API) Recommended Practice 752, “Management of Hazards Associated
with Location of Process Plant Buildings.” API 752 states that each company
may define its own risk and occupancy criteria.


7. API 752 is a widely recognized practice for complying with facility siting
requirements under the Process Hazard Analysis element of OSHA’s Process
Safety Management Standard (29 CFR 1910.119).

8. API 752 provides no minimum safe distances from hazardous areas for trailers
used in refineries and other chemical facilities. Trailers are not generally designed
to protect the occupants from the fire and explosion hazards present in refineries.
In contrast, occupied buildings (e.g. control rooms, operator shelters) located
within a process unit are typically permanent and constructed to be blast and fire
resistant.


9. Trailers can be easily relocated to less hazardous sites. Subsequent to the March
23rd incident, BP America Inc. announced that it would move trailers at least 500
feet from hazardous process areas. A number of contractor offices were moved to
an offsite location.


10. In 1995, another serious process plant incident involved occupied trailers placed
too close to hazardous areas, resulting in significant deaths and injuries. At the
Pennzoil Refinery in Rouseville, Pennsylvania, a hydrocarbon fire that resulted
from the bursting of two storage tanks led to five fatalities, including two
contractors who were in trailers sited near the tanks. A 1998 EPA investigation
report determined that if the trailers had been isolated from the storage tank area
the casualties may have been prevented.


11. Under 42 U.S.C. §7412(r)(6)(C) (ii), the Board is charged with “recommending
measures to reduce the likelihood or the consequences of accidental releases and
proposing corrective steps to make chemical production, processing, handling and
storage as safe and free from risk of injury as is possible ….”


12. Board procedures authorize the issuance of an urgent safety recommendation
before a final investigation report is completed where there is a likelihood that a
safety issue is widespread at a number of sites.


Accordingly:

Pursuant to its authority under 42 U.S.C. §7412(r)(6)(C)(i) and (ii), and in the interest of
promoting safer operations at U.S. petrochemical facilities and protecting workers and
communities from future accidents, the Board makes the following urgent safety
recommendations:


American Petroleum Institute

In light of the above findings concerning the March 23rd incident at BP’s Texas City
refinery, revise your Recommended Practice 752, “Management of Hazards
Associated with Location of Process Plant Buildings” or issue a new Recommended
Practice to ensure the safe placement of occupied trailers and similar temporary
structures away from hazardous areas of process plants. Ensure that the new
recommended practice:

* Protects occupants from accident hazards such as heat, blast overpressure, and
projectiles;

* Establishes minimum safe distances for trailers and similar temporary
structures away from hazardous areas of process plants;

* Evaluates the siting of trailers under a separate methodology from permanent
structures, since trailers are more susceptible to damage, are more readily
relocated, and likely do not need to be placed near hazardous areas.


American Petroleum Institute and the National Petrochemical and Refiners
Association

Issue a safety alert to your membership to take prompt action to ensure the safe
placement of occupied trailers away from hazardous areas of process plants.

 

[BlastRep]

Stephen - I have been involved in the design and manufacture of Blast Resistant Modular Steel Buildings in Petro-Chemical Plants since 1998.

Utilization of steel modules versus CMU is more cost effective and allows for permanent and/or temporary structures. Generally, a module is built to withstand a predetermined blast criteria identified by the owner. If you have any specific questions, I would be more than happy to attempt to answer.

 

[sshep]

StephenPL,

At our USA gulf coast plants we have gone to using modular metal buildings for field TAR work. These are basically modified sea containers. A typical building has a blast restant door installed in one of the long sides, and space for one or two offices inside. These can be rented or purchased as either a shell, or completely outfitted internals (including aircon, heat, etc).

Our mechanical department gave me the following contacts:

http://www.safehavenenterprise.com

http://www.hazardousmaterialbuildings.com/explosion_relief_panels.html

http://www.bebcotest.com

best wishes,
sshep

 

[pennpiper]

Both of these last two contributers, BlastRep (Structural) and sshep (Chemical) have provided good information. The term "blast resistence" is used and as we all know, is somewhat possible depending on cost. One of these contributions offered information on internal blast effect mitagation. The original question did not relate to internal explosions. As good as they are these comments reinforce the fact that there is no such thing as "blast proof."
The API recommendations listed above are still the best advice.
When in doubt, keep them out!

 

[JStephen]

It seems they are supposing that if a trailer is moved out of a hazardous area, then whoever would ordinarily be in that trailer would be moved as well. How true is this? I'm thinking if this is a foreman doing construction work on site, moving the trailer a half mile off would just mean he didn't use the trailer any more.

 

[JOM]

Maybe the fundamental question is why the personnel were located at this place. Was it essential or merely practical?

Perhaps we'll learn more when the CSB release their final report.

J.

 

[BlastRep]

The simple removal of standard office "trailers" from the blast zone most often leads to other harzardous situations.

Case 1: Vehicles are now being utilized to perform paperwork and somtimes for breaks within the blast zone. Vehicles are not blast resistant, yet now they are a substitute offices, lunch rooms, etc.

Case 2: Construction and maintenance operations will see an increase in cost associated with projects. Maintenance, operations and warehousing being located sometimes up to 2 miles from the work zone can lead to improper tool and parts utilization. If an integral part, something as simple as a bolt, is 2 miles from the work area will the personnel stop operations and make a 15-30 minute roundtrip for the proper bolt or make an inadequate field substitution?

Plants will see project cost increases of up to 45% working by simply moving outside the blast zone. With strategic planning in advance of projects, blast resistant modules can alleviate most if not all of these unsafe practices.

Blast resistant modules only look like modified sea containers, however they should be specifically designed to resist the blast that is determined during the "Siting Analyses" which should be performed previous to the placement of any blast resistant structure.

Another recommended manufacturer is:

http://www.mbindustries.com/

 

[schnipp]

I was under the impression that the specific case of the BP Texas City explosion was that all of the deceased were in a post-shutdown review meeting. Something that absolutely did not need to be taking place within 121 feet of an isom unit.

 

[mw001]

I am in need of the specific design criteria and codes for the construction of a Petro Lab Analysis building sited on a Petro Plant facility. I need to determine the minimum separation distance the proposed building can be from the refinery area...as well as blast resistant concrete tilt wall construction.

 

[IFRs]

API just published a new document on this very subject.

 

[bchoate]

BCHOATE
Several comments on this thread come to mind pertaining to process safety. We can find many reasons why we want a building practically on top of the job. But process safety tells us when that is practical and work discipline and auditing of the same make the safe solution work. This issue pertains to normal operation of processes as well. Where and why do we site control rooms, labs, etc.

Proximity of occupied buildings should be based on the materials and quantities in unit operations (potentially also) and calculations of blast overpressures for each material. Permanent buidlings can withstand blast overpressure of 1 psi with repairable damage. If the blast overpressure is above 1.8 psi, normal permanent buildings will not likely escape total loss. This is a conservative guideline. Hardened buildings can withstand higher overpressures but the cost of the building increases rapdily with the degree of hardening. There are few buildings that will survive a near ground zero shock wave from a explosion. Siting of temporary buildings should be based on calculations of potential overpressures from unplanned events. Prudent siting would be outside the 1 psi pressure circle. Calculations should account for structures adjacent to the blast site since the blast wave is often intensified by reflections off nearby structures.

The choice is safety or convenience. Safety must be dominant. What reasoning compels siting of personnel in close proximity to a potential explosion.