Petroleum Storage Tank Facilities – Part 3

FIRE SUPPRESSION

Petroleum Storage Tank Facilities – Part three

by Brenna ShumbamhiniJune 9, 2022

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In earlier installments of this collection we talked about the types of petroleum storage tanks, their places, frequent hearth hazards, described the kinds of fires, and fire suppression methods that storage tanks could have.
In this third and last article we’ll discuss firefighting strategies and ways in addition to pre-incident response planning fundamentals.
Firefighting Strategies and Tactics

Firefighting methods and ways begins with a well planned and tested pre-incident response plan. This shall be discussed later within the article. Storage tank fires are advanced events. These fires will require the implementation of plans, preparation, proper utilization of assets, and an intensive logistics part to ensure the sources can be found and arrive on scene in a coordinated and well timed trend. The following strategies and tactics for firefighting presume that the planning and preparation levels have been performed by plant and fireplace department personnel. Experience tells us that successful and protected extinguishment of tank fires can solely be achieved when based on planning and preparation, with all related taking part in all elements of the process in addition to the exercising of the plan. Exercising the plan may be conducted with desk top eventualities as properly as periodic full scale workouts.
As quickly as a fire division receives notification of an incident, size up and intelligence gathering ought to be started. Information must be gathered rapidly to start the event of firefighting methods. The following must be thought of:
Rescue of personnel within the immediate area

Life security hazards to website personnel

Extension

Confinement

Extinguishment

Environmental impression

Community influence

After the instant points are addressed, we have to identify the sort of fire current:
Vent fireplace

Seal hearth

Piping-connection fire

Full surface involvement fire

Once we now have examined the above information we will then begin to develop our useful resource list and incident motion plan (IAP). Remember that the kind of product concerned may even impression our resource needs and tactics. The following are various forms of fires and firefighting tactics:
Ground Spill or Dike Fires

These fires may be considered as simple pool or spill fires. Calculate the realm (length x width) and use the correct utility price primarily based on NFPA 11, Standard for Low-, Medium-, and High-Expansion Foam. Knowing the product will also provide the right type of foam concentrate and application technique. Alcohol products would require a gentle utility methodology. Firefighters shouldn’t enter the dike space until protected to take action and approved by the Incident Commander in session with the incident’s Safety Officer. Atmospheric testing should be carried out prior to and during entry. Exposures similar to tanks, related piping, and pumps should be protected with water by way of ground or fastened monitors. Ground fires should be extinguished first, then using dry-chemical equipment, valves and flanges extinguished. The most effective gear for these mixed fires could be hydro-chem™ technology whereby foam/water resolution in addition to dry-chemical can be delivered simultaneously via the identical nozzle.
Specialized moveable monitor placed on lip of storage tank.
Rim Seal Fires

Rim seal fires can often be extinguished using the fastened or semi-fixed foam techniques if put in and properly maintained. On external floating roof tanks, if the mounted or semi-fixed fire safety methods are not current, handbook firefighting will must be performed. Under the safety of a water spray, a firefighting crew will ascend to the gauging platform with hand-held foam gear. The major methodology ought to be using foam wands to capture the fireplace (Photo 1- Foam Wand) which allows the position of specialised displays to be positioned on the lip of the tank. (Photo 2- Specialized transportable monitor) The displays can then be used to extinguish the rim seal fireplace using the reach of the monitor so that hoselines and personnel are not working from the wind girder away from the ladder. If this gear just isn’t obtainable, then foam hoselines could probably be used from the wind girder. This is a hazardous operation, and solely undertaken if there is a structurally protected wind girder with handrails. (Photo 3- Foam chamber and Wind Girder) Personnel should be secured to forestall falling.
In some cases, elevated streams from hearth autos have been used. This just isn’t a major methodology of extinguishment. It has been noted that there’s at all times an opportunity of sinking or tilting the roof underneath the excess water/foam answer, thus creating a larger downside, which may embody an obstructed /unobstructed full floor hearth.
On tanks fitted with inner floating roofs, these fires could additionally be thought of rare, but they do occur. They might be extremely troublesome to extinguish until mounted or semi-fixed fireplace safety techniques are installed. Foam chambers and foam dams are the best, and the design of the system ought to be calculated on a full surface hearth, especially if the pan under is aluminum.
The most tough technique of extinguishment in a lined floating roof tank might be to shoot foam water answer via the eyebrow vents. Using hydro-chem™ into these vents has proven efficient prior to now.
Full Surface Fires

Staffing requirements for a serious tank fireplace will differ depending on the kind of tank, location, water supplies, nature of the incident and the availability of trained personnel. Attacks on these fires will predominantly use the Type III “Over the Top” method of extinguishing agent delivery. The product involved will decide the required foam application fee and share of concentrate to water flowed. The measurement of the tank will also decide the application fee. For larger tank diameters a bigger software fee is required. The chart under is accepted by industry consultants to be the minimum utility rates primarily based on the tank diameter:
Table 1– Application rates

Foam resolution (foam concentrate + water) flow charges to be established are primarily based on the next formulation:
Foam answer circulate fee = Tank floor space x application rate (as noted in table 1)

Tank surface space = 3.14 x radius2

Application fee = as per desk below

Foam Concentration Flow Rate (lpm [gpm] of froth concentrate)

Foam focus flow fee = Foam solution move rate x foam %

Foam % = 1%, 3%, 6% relying on sort of froth, product on fireplace and manufacturer’s recommendations

Foam Concentrate Quantities

Foam concentrate move rate (lpm or gpm) x period

Duration = sixty five minutes for Type III (over the top) functions

Please observe that these portions are for extinguishment purposes. For vapor suppression after extinguishment it is an accepted apply to double our extinguishment provides to maintain the suppression of vapors and prevent the attainable reignition of the product.
Some of the above flows may be well in extra of 37,854 lpm (10,000 gpm) and will require massive capacity supply devices similar to large trailer mounted displays and large transportable pumps.
Now that we all know our flow rates and foam concentrates required we have to additionally look at different factors similar to:
Position and condition of roof drains

Volume of the product

Status of tanks and valves

Depth of water bottoms

Structural situation of tank

Product in tank and its physical properties

Is there room in the tank to accept the entire foam resolution with out inflicting an overfill

What different tanks, piping, or buildings could also be exposed

Wind course

Weather situations (present and expected)

Foam chamber on tank. Note the wind girder with appropriate handrail. If the foam chamber was not present or didn’t perform correctly, the wind girder could be used to advance foam hoselines for seal hearth extinguishment.
In any hearth state of affairs we want to contain the local facility personnel in our planning section as technical specialists. They may be on the command submit advising the Incident Commander directly. These fires are not our odd ‘bread and butter’ operations and must be handled as an incident that can change rapidly and unexpectedly, typically with severe penalties. Do not attempt to extinguish a full surface hearth with out all needed resources on the scene. Cooling of adjacent tanks would be a tactic to be used prior to all foam supply and personnel resources are on the scene. The cooling of the tank that is on fire is not beneficial unless full 360 diploma cooling can be completed, which is uncommon. Also, when cooling a tank, use solely the amount of water needed. When the cooling water stops turning to steam, you might shut down the streams and start them up again when necessary. This will conserve water provides for extinguishment and cut back the water flowing into the dike areas. Generally between 1,893 lpm (500 gpm) and three,785 lpm (1,000 gpm) might be required for each tank cooled. In addition to the right delivery gadgets and foam supplies, we need to ensure that our foam answer supply zone on the surface will be capable of spread out as quickly as it hits the surface and canopy the entire floor area. According to the National Fire Protection Association (NFPA) foam can journey effectively throughout a minimum of 30m (100 ft) of burning liquid. We believe that for calculating foam runs, this number ought to be lowered to 24m (80 ft), ensuring that our landing zones journey and overlap one another. Firefighters should pay attention to the distance a master stream can reach as well as the touchdown zone length and width. These could be obtained from the producer of the monitors and nozzles and verified in the area during drills and workout routines. By figuring out this information we will pre-plan the positioning of our master streams. Range finders can be used during operations to gauge distances to the tank to assist with monitor positioning. There are a few occurrences that may occur at a storage tank fire that the fire service ought to concentrate on. These are:
Slopover

This event can happen when a water stream is applied to the recent surface of burning oil, offered that the oil is viscous and the temperature exceeds the boiling level of water. It causes a short length of slopping of froth over the rim of the tank with a minimum of depth.
Frothover

Frothover is a steady, sluggish transferring froth over the rim of a tank and not using a sudden and violent response. Frothover might occur when the tank just isn’t on fire and water already inside the tank is obtainable in contact with sizzling viscous oil which is being loaded. An example is when hot asphalt is loaded right into a tank automobile and comes into contact with water within the tank, causing the product to froth excessive. During a fire with crude oil it may also occur when the warmth wave created by the burning crude oil reaches the water layers (stratums) within the crude oil. This heat wave will convert the water to steam, inflicting a frothover.
Boilover

This occasion is a sudden and violent ejection of crude oil from the tank due to the response of the hot-layer and the accumulation of water at the backside of the tank. The gentle fractions of crude oil burn off, producing a heat wave within the residue. The residues with their associated heat wave sink in direction of the bottom of the tank. This warmth wave will ultimately attain the water that usually accumulates on the bottom of the tank, and when the two meet the water is superheated and subsequently boils, expanding explosively causing a violent ejection of the tank contents and fireplace. The expanding contents being expelled can journey the distance equivalent of ten tank diameters. Careful consideration must be given during pre-incident response planning of the placement of the command submit, staging areas, rehab, equipment placement, and so forth.
Pre-Incident Response Planning

When planning for a response to a petroleum storage tank facility it is best that the information gathered is done on-site and with the help of facility personnel. While on site, entry roads that you would be use to access the realm and place fire equipment (appliances) should be pushed by the automobiles that shall be used throughout an incident. Many occasions the turning radius of apparatus is merely too great to make the turns wanted in the facility. Swales or culverts may impede apparatus. If the equipment chassis is too long and or low, it could grasp up or ground whereas traversing a swale or culvert. Bridges on website might not enable the burden restrict of new equipment, preventing its use at an incident.
During pre-incident response planning info that must be gathered includes the next:
Tank sorts, dimensions, contents and capacities

Pipe isolation valves, locations, and operating mechanism

Fixed fireplace safety systems out there

Access points to facility and tank

Contact cellphone numbers

Locations and operation of emergency shutdown units (ESD’s)

Availability of firefighting resources

Water provides

Pumping requirements

Foam focus necessities

Mutual/automatic aid available

Other data can be obtained based on the wants and requirements of your division. While these articles are not completely inclusive of all data that a hearth department must know, it’s a good start. Other resources are listed at the end of this text. It is necessary that firefighters attend classes on this specialised firefighting, pre-plan these facilities, and exercise the pre-plans. Don’t permit these facilities to become part of the panorama. Visit these amenities and ask questions!

For extra data, go to www.worldsafeinternational.com

[su_note]Resources

American Petroleum Institute [API]. API Recommended Practice 2021: Management of Atmospheric Storage Tank Fires. Washington, DC: API, 2001, Reaffirmed 2006 Hildebrand, M. S. & Noll, G. G. Storage Tank Emergencies: Guidelines and Procedures. Annapolis, MD: Red Hat Publishing, 1997 Institution of Chemical Engineers [IChemE]. ราคาเกจวัดแรงดันลม : Liquid Hydrocarbon Tank Fires: Prevention and Response. Rugby, UK: IChemE, 2005 Shelley, C. H., Cole, A. R. and Markley, T. E. Industrial Firefighting for Municipal Firefighters. Tulsa, OK: PennWell, 2007References 1.
Shelley, C. H., Cole, A. R. and Markley, T. E. Industrial Firefighting for Municipal Firefighters. Tulsa, OK: PennWell, 2007.[/su_note]

Top Image:- Foam wand being placed throughout coaching. Note the protective hose stream in place.
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