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Rain, Rain Go Away ... Locating in bad weather

Photo by Erik Witsoe on Unsplash

When I was still at primary school, a long time ago, I recall complaining to my Dad on a wet and rainy day that we couldn't get a ride to school. His reply was "Son, you're not water-soluble" as he handed me a raincoat.

As far as I know, my solubility properties haven't changed since then. Which brings me to writing this blog on a very wet day while stuck in the office.

Wet weather is not a Locator's friend, and it has nothing to do with not wanting to work in the rain or a fear of getting wet. The fact is it's merely impractical in most cases to be locating and marking in wet conditions. 

The standard mark out paint used for locating can have a longevity of years when applied to hard surfaces in dry conditions. In the rain, mark out paint's adhesion to most surfaces is almost zero. Even if you get paint on the ground the next rainstorm is likely to erase that fabulously painted 33kV underground cable you just located.

As a Locator, I'm more than happy to return and remark all the work I did yesterday in the rain if the client is paying. However, it seems both wasteful and unproductive to complete work, knowing it will have to be redone.

The other concern a Locator will have is water damage to their gear. 

Almost all of our standard locating equipment has an IP rating stated by the manufacturer. For example, the well-loved Radiodetection RD8100 has an IP rating of 65. This means it's dust-tight and protected from the harmful effects of a water jet applied at a specific pressure for a limited time.

Exposure to rain for 6 or so hours is bound to allow some water entry, especially with older equipment where seals are worn, or joints have opened. Looking after trusted gear is very important to a Locator, and they'll be reluctant to risk any severe water damage to the internal components.

Paint doesn't stick in the wet

Paint doesn't stick in the wet

Another wet weather issue is standing water. 

When a Locator has completed all their EM work, they'll probably expect to run a GPR over the area to confirm what they've found and to locate other services. Pools of standing water pose two problems for your GPR. 

The first goes back to the potential for water damage. The second to do with the effect pools of water, or a high water concentration in the surface layer, will have on your imaging.

Standing water and high surface water content will almost certainly limit the visibility of subsurface objects in your GPR imaging. 

There is a high possibility that you will miss something that would be apparent in dry conditions. Combined this with your expensive GPR not taking kindly to being pushed about on a muddy work site and you have another excellent reason to pack up your kit and head to the office.

I'm sure most Locators, like myself, would be happy to wrap up in wet weather gear and box on when the heavens open. In the end it is unproductive, potentially risky, and likely to be damaging to equipment.

Standing water is an issue for GPR

Standing water is an issue for GPR

So the next time your Locator packs up and heads back to the office when it's raining, rest assured it's not because they are water-soluble.

Just a note from experience, if your gear does get wet in the field, make sure it gets dried out at the end of the day. Never store damp equipment, even overnight.

It's Winter in NZ at the moment... so stay dry out there people.

Innes Fisher Thumbnail

Innes Fisher is the founder and Managing Director of Utility Location Services New Zealand. He is a professional certified Locator active in the field and the New Zealand damage prevention community. Past President of Nulca New Zealand, international speaker and author.