Home Podcasts THMG042 – Grounding and Bonding, Part II

THMG042 – Grounding and Bonding, Part II


In this episode, we conclude our discussion on grounding and bonding and how they affect us as hazmat techs.

Complete Show Notes

1:00 The Role of the NFPA

  • National Fire Protection Agency (NFPA) addressed the need for grounding and bonding in NFPA 30 (Flammable and Combustible Code)
  • Chapter 18, 5.2.2 states that “the means must be provided to minimize the generation of static electricity when transferring flammable liquids”
  • NFPA 77 recommended practice on static electricity covers principles of managing a static environment
  • NFPA provides strongly-worded suggestions, while OSHA writes the actual laws
  • Keep static electricity below 1k ohm on-scene during hazmat response operations
  • NFPA states that “in a field-based operation, it might be necessary to establish a temporary emergency grounding system in a remote location in order to dissipate static charges. In such situations, various kinds of ground conducting electrodes can be used, such as rods, plates, and wires; sometimes used to increase the surface area with the earth
  • This means you can do whatever it takes to achieve a safe response area that properly dissipates the danger of static electricity
  • Static electricity is generated by the movement from one container to the other

5:40 The Role of OSHA

  • OSHA requirements for grounding and bonding are in their flammable liquids section (29 CFR 1910.106 E6II)
  • Regulation states that “Category 1 or Category 2 flammable liquids or Category 3 flammable liquids with a flash point of below 100 degrees Fahrenheit or 37.8 degrees Celsius shall not be dispensed into containers unless the nozzle and the container are electrically connected where the metallic floorplate on which the container stands while filling the electrically connected system or where the stem is bonded to the container during filling operations by means of a bond wire, the provisions of this section shall be deemed with and complied with”
  • This means that when we go to the gas station to fill containers or get gas for our vehicles, the nozzle must be in contact with the container (bonding) and both the container and pump need to be on an electrically-grounded site

8:50 Establishing a Ground Field

  • Technicians must test the ground resistance using a ground earth resistance meter (i.e. the megger)
  • For bonding and grounding to be effective, a metal-to-metal connection must be maintained between the bonding and the grounding wires and the containers – everything is electrically connected
  • When done properly, this removes 3 of the 4 factors of ignition below:
    • A means to generate a spark – continual flow of the product increases static charge over time, so removing this accumulation lessens the ability to generate a spark
    • Enough static charge to bridge the gap – grounding all the transfer appliances between the containers reduces the total amount of availability to bridge the gap, thus eliminating the charge to create a spark
    • A spark with enough energy to ignite – grounding and bonding reduces ignition energy to keep it below its peak sparking level (especially important in flammable atmospheres) – there are meters and monitors out there that help you determine whether an atmosphere is flammable
  • Weather can be significant – colder temperatures mean more static because it’s dryer (less humid) in the winter

10:40 Hazmat Drill Nugget from Hazsim Training Systems

  • Sampling a drum with a tube to get a layered-type effect
  • Practice this in the firehouse or back at the station – it can be difficult

17:00 Grounding and Bonding On the Scene

  • Start by making the actual connections to welded, unpainted, and non-oxidized materials – these are all insulators
  • Even materials that look like pure metals should be scraped to double-check if they’ll work
  • Take the bundle of wire, walk up to the bad tank, and connect it first – then, go back to ground and do it there
  • If you do this in the opposite order, you might produce a small spark, which can be disastrous – always keep your flammability meter with you
  • Next, walk over to the good and connect it – then, walk the wire away and put it to the ground – this completes our grounding scheme
  • Always take your possible potential difference by clipping onto the bad tank and walking over to the good one
  • Use salt or SpeedyDry in water to increase its conductivity – offers improved grounding and allows for more surface area to make contact
  • Or, use more metal to make the field bigger – use as much as need be or as much will fit; every rod you use increases your resistance by about 40%
  • If you work in a large city, you have to think outside the box – try grounding to fire hydrants, metal barriers on the side of highways, metal fences, etc.

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