How to Safely Earth a Solvent Tanker During an Emergency Transfer?

Dear Seniors,

In the following situation, how to provide earthing to a tanker: If a solvent tanker is involved in an accident and another empty tanker is arranged by the consumer to transfer the solvent, how should earthing be provided to the tankers?

Regards,
Abhay

Dear Abhay,

First, I want to thank you for being the one to raise questions in our EHS forum. I appreciate your interest. Sorry for the late reply.

Earthing Facility for Flammable Liquid/Solvent Container Trucks

All flammable liquid/solvent container trucks have an earthing facility. You can check with fuel container trucks to understand better (please find the attached photo). However, in this particular case, there is a difference. Remember that all flammable liquid/solvent container trucks have an earthing facility.

Steps to Ensure Safe Fuel Transfer

If a truck is involved in an accident and you need to transfer fuel, you should first check for the nearest earthing point or location. If you find one, connect with the earthing and then start the transfer of flammable liquid/solvent. If there is no available point near the accident area, you will need to arrange an earthing rod, place it on the ground, and then make the connection. This method is the easiest and safest way to proceed.

Please see the attached photo for reference:
- Fuel tanker
- Fuel truck earthing
- Fuel truck earthing connected with earthing rod

I await your instructions.

Thanks and stay safe,

Raghu

Before giving an answer to this question, I would like to clarify the need for earthing. Earthing of any tanker or vessel is necessary to equalize the potential difference between the earth and the tanker due to static charge accumulation during the movement and transfer of liquid or gas.

Now, if you are transferring the material from one tanker to another, the procedure shown in the photos is acceptable if both tankers are earthed. Alternatively, you may connect both tankers together to reduce the potential difference.

Regards

Dear Vino,

Yes, you are right. Before we transfer flammable liquid/solvent, we need to equalize the potential difference between the earth and the tank.

Sr. Electrical Engineering Command on this Case:
In this case, he advised bonding the earthing cable together (truck to truck) and then connecting it with the earthing rod. It's the easiest and safest way.

Vino, do you remember one thing: if a vehicle is under repair, we can transfer flammable liquid/solvent as long as we check the earthing or grounding and use the right type of equipment to transfer the flammable liquid/solvent (like a hose). However, if a vehicle is involved in an accident, the fire department guys are the only ones responsible for transferring the flammable liquid/solvent.

• As per OSHA and EM-385, it covers basic earthing or grounding only.
• If you want more details, check with the fire engineering guys or petrochemical guys. The fire department guys have a different or higher standard procedure for this process.

Hope this helps.

Thanks and be safe,
Raghu

Connect the earth to an earthing rod, and this rod should be buried in the ground. Do this for both tankers independently. Bonding should be carried out separately for the tanker hose to ensure electrical continuity and prevent static buildup. Your electrical engineer is the competent person to advise on the best practices in this matter.

Hope this helps.

Thank you and best regards,

Dear friends, Nice, and we are really on to an interesting topic. The discussion is heading in the right direction. Here, may I ask you a few simple questions about the tanker earthing?

- Is its resistance ever measured?
- If so, what was the result?
- What is the maximum resistance it can have for effectiveness?
- What depth do we have to drive that rod to get a reading for effectiveness?

Those in construction use copper rods with clamps to do the earthing. Quite often, we can easily pull out the rod, or the rod will be slanting, not driven beyond two to three inches for the hard ground. Those rods are usually not driven deep enough to provide the required earthing. Again, in the desert, the sand is quite dry and often hot. An earthing for the sake of earthing!

Let us clarify and get the best out of the discussion. I earnestly request youngsters in the field to get involved. Let it be foolishness you post, but only connected with the topic under discussion. Please spell out your understanding. Someone knowledgeable in the forum will definitely help us to improve ourselves.

Regards, Kesava Pillai

@ Kesava sir,

Thank you for monitoring us. As a tanker has an iron rod, wires, and sometimes a water carboy (to wet the earthing pit area), can they use it as an emergency earthing arrangement?

Regards, Abhay

The topic under discussion is really interesting. I would like to add that in all cases, it is essential to ensure that static electricity and the electrical potential should be zero on all parts of the tankers in question. For this to happen, a proper earthing arrangement is required with thick and highly conductive material to keep the earthing resistance as low as possible or equal to the value prescribed, depending on the type of fuel being transferred.

Hope this information is helpful to some extent. Values of earth resistance can be determined through the Indian Electricity Rules for this particular section of the topic.

Thanks and regards,
xbkmaju

Great participation from all of you in the thread... Good and appreciable one... I have never come across more on the topic... Diesel & HCL are coming to our plant on such tankers... We are ensuring earthing before transferring the same into the tanks... After going through the entire discussions now, I feel the importance of this... I remember those early days at the start of our plant; we were transferring diesel and all from tankers to tanks without even fixing an earthing... Even when talking to the driver of the tanker, he was aware of the fact that the tanker needed to be earthed but just neglected the same as nobody forced him to do so and also there was no arrangement...

@ Keshav Sir, now let me share my understanding on the topic and expect to get the right answers.

Tanker resistance ever measured? = No. Please let me know how we can measure the resistance of the tanker? (Chemical Handling or Diesel Handling Tanker)

And if so, what was the result? - Never did such a resistance test.

What is the maximum resistance it can have for effectiveness?

Resistance is basically between two points. Between which two points are you measuring resistance? Resistance for effective earthing should be less than 2 ohms. 0.8 ohms is the ideal value.

What depth do we have to drive that rod to get that reading for effectiveness?

It depends on soil resistivity, number of electrodes used for the grid, etc. As a common practice, we used to drive the depth up to which the ground soil retains its moisture even in peak summer. Soil moisture helps in homogeneous connectivity of the electrode with the earth mass and hence helps in getting low earth resistance. You can say more than 3.00 meters.

Now, can anyone please help me in answering the following few questions?

1. What should be the ideal material used as an earthing rod & connecting material between the earthing rod & tanker for effective earthing?

2. Suppose the Storage Tank is earthed to one earth pit. Can we connect the tanker earth to the same earth pit?

@ Abhay, first of all, thanks a lot for bringing such a topic for discussion... Once again, requesting you to not bring too many threads at the same time for discussions... Give time to all members to participate... Keep a gap of at least 3 or 4 days... Let's try to get the best out of the forum... Safety is a vast subject, hence let's try to learn a little at a time... By seeing a lot of threads at a time, all will get frustrated and nobody will participate... If there is anything that needs immediate attention, post at any time, but out of curiosity, please don't bring a lot of topics together... Hope you will take this positively...

A lot of new members are starting to participate actively... Welcome all and share your expertise with us, please...

Regards,
Dipil Kumar V

Dear Shailesh, if it's possible, please post the photos of the arrangements made for the earthing of tankers. That will be very useful.

Regards,
Dipil Kumar V

Your use of an iron rod is of no use and is not acceptable. Having a meter of copper earthing rod of half-inch diameter, driven at least half a meter deep into the ground with undisturbed soil, if well wetted, will normally meet the requirement in Indian conditions to ensure protection against static electricity. Bonding and earthing are different, and in that effect, you still have to adopt proper methods.

Regards,
Kesava Pillai

Thank you for your valuable reply. Could you please provide perfect answers to the queries raised by you:

Here, may I ask you a few simple questions about the tanker earthing? Is its resistance ever measured? If so, what was the result? What is the maximum resistance it can have for effectiveness? What depth do we have to drive that rod to get that reading for effectiveness?

I have discussed the same with a few electrical engineers, but nobody was able to provide ready-made answers, and even after referring, they gave different replies...

Hope to receive a positive reply from your side.

Regards,
Dipil Kumar V

We are going to buy an Earthing kit for unloading/loading tankers at our plant. When it is fixed, I will definitely post photographs.

Acknowledgment

Keshav Sir, you have provided really good answers to all queries. Thanks for guiding us.

Regards,
Shailesh

Dear Dipil,

Earth Resistance Measurement

Earth resistance measurement may vary from 0.5 to 20 ohms. Any reading above 20 ohms is not acceptable. In generating/substation settings, the earthing resistance is typically very low, sometimes as low as 0.5 ohms.

In terms of earthing for tankers to protect against static charge, the necessary information has already been provided.

Regards,
Kesava Pillai

Thank you very much for your reply. Let me share the same with my colleagues, and I will definitely get back to you if anyone has any specific comments.

Regards,
Dipil Kumar V