Environmental Science & Engineering - www.esemag.com - November 2005
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The dangers that lurk in tank farms

By Barry Jasper and Dave Hill

Try this one minute quiz on tank farm dangers:

Do you have a process that defines and identifies confined spaces in your facility? Yes or No
Have you completed a documented risk assessment of each of these spaces? Yes or No
Do you insist that your personnel measure for possible contaminants, in every extremity of the space to be entered? Yes or No
Are the instruments used for atmospheric sampling, calibrated monthly, and functionally bump tested, prior to each day’s use? Yes or No
Is it practical, and are you able, to complete a non-entry rescue, from all your confined spaces? Yes or No
If not, do you have a trained rescue team, to remove any worker in a space, who experiences difficulties? Yes or No

If you answered no to any of these questions, you could be out of compliance with the Canada Labour Code, and in Ontario, with Regulation 851 and/or 213 of the Occupational Health and Safety Act, and with its proposed successor, the Harmonized Confined Space Regulation, which will apply to all sectors, including the construction and agricultural industries.

A documented risk assessment should include all of the potential hazards within the space, the means of neutralizing these hazards, and a list of all equipment required by the entrant and attendant, to safely make the entry. All of the following items need to be taken into consideration, and form part of the entry plan:

Isolation, lock-out and tag-out of all mechanical, electrical, hydraulic, and pneumatic equipment.
Control of any sources of ignition.
Movement of materials.
Ventilation techniques and purging, use of positive and negative pressure.
Explosive and flammable atmospheres.
Means of communication between the entering team and the outside attendant.
Methods of overcoming the inherent difficulties of limited access and egress.
Choice of personal protective equipment.
Selection of safety equipment.
Consideration of the regulations regarding fall arrest if the distance from the entrance to the floor of the vessel is greater than 10 feet, or if the entrance is above grade.
Atmospheric testing, choosing the right meter for the job, and the correct atmospheric survey test points to cover the space and all the possible contaminants.
Emergency equipment and emergency response procedures, Entry and Non-Entry rescue provisions.
Warning signs and barricades.
Schedule of frequency of communication checks for normal entries; plus reduction factors for entries made with supplied air, or in protective suits in high temperatures.
Spaces should be divided into four categories, using the following criteria, and records kept of all personnel training, to ensure that the entry team has the knowledge to deal with the class of entry to be made.

Summary of types of confined spaces Each step in the type of confined space entry reflects the escalation in the associated risks or hazards of the entry; therefore the level of protection also escalates.

TYPE 1 - No atmospheric hazards exist, and written documentation confirming this fact is contained in the permanent record.

TYPE 2 - An atmospheric hazard existed but was made safe through ventilation. Measures necessary to maintain a safe atmosphere have been implemented. An attendant is posted, arrangements made for rescue, and someone skilled in CPR is available.

TYPE 3 - A hazardous atmosphere exists and cannot be removed. Additional measures are required such as suitable respiratory protection, safety harnesses and rope as well as other required personal protective equipment.

TYPE 4 - A flammable or explosive atmosphere exists. Therefore the following limitations apply:

Entry for inspection, concentrations < 50 % LEL
Cold work < 10 % LEL
Hot work 0 % LEL

Where LEL is the lower explosive limit of the contaminant.

Is 911 your main line of defence? Can you rely on it? Sadly the answer is in the negative for all the following reasons. Fire departments train each of their staff in structural fire fighting, then in a number of specialized fields. Since, in practice, the number of confined space incident calls they receive is far lower than those for paramedic assistance, vehicle extrication, water rescue, high angle rescue, and ice rescue, fewer people are trained in this specialty.

Very few fire departments have equipment for confined space rescue, and even fewer have current training. This year there were two incidents involving road tankers in tanker cleaning facilities. In one instance the cleaning staff survived; in the other, the rescue turned into a confined space recovery. Why is that?

Put very simply, the math was not on their side:

If an individual is deprived of oxygen in a confined space, clinical death occurs after three minutes, biological death after six minutes.
The average response time for a full time fire department is four minutes, for a part time department probably double that.
Add to that the time needed to reach the space, then the time to do risk assessment and the clock is running faster than the feet can get there.
If you have teams entering spaces without rescue plans in place, your 911 call will probably only put in place a body recovery response.
Don’t for a second dismiss the possibility of a problem, because your tankage doesn’t contain any potential for finding exotic chemicals.
Remember last year’s Vancouver barge incident, where three workers and a firefighter went down, and only one survived. There were no contaminants involved, the barge was simply rusting so aggressively, that the oxygen levels were depleted to such low levels that life was unsustainable.
Don’t for a second dismiss the possibility of a problem, because your crew has atmospheric metering capabilities.
Ninety per cent of confined space incidents result from using the wrong meter for the job, meters that have become inaccurate, or atmospheric surveys that are flawed or not maintained continuously.

Contact:Barry Jasper and Dave Hill are with Echelon Response & Training Inc.,
E-mail: barryjasper@echelonresponse.com

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