Diving Platform Grounding

[Sconnie]

We are working on a new natatorium for the local university, and the concrete 10 meter diving platform is being revised from uncoated to coated rebar. This simple change has surprisingly complicated things, as bonding the original uncoated rebar was easy but I am now unsure how to install the equipotential bond to a vertical structure. Do we simply follow the perimeter surface rules per 680.26(B)(2)? If so, do we carry the bare #8 solid up the structure to bond the hand rails, etc? The code doesn't specifically address diving platforms, but it seems to make sense to bond all metal parts of the structure no matter how high they are. The consultant gave me the "bond per code" answer and the AHJ has been ambiguous about it and will wait to see what I do then decide if it's right or wrong, so I'd at least like to start in the right direction. Any input is appreciated.

 

[Little Bill]

If the concrete for the platforms hasn't been poured yet, you could run at least a #8 in the concrete up to the top to bond the metallic parts.

Personally, I fail to see how there would be a potential difference at the top of the platform since you couldn't contact the ground and top at the same time.

 

[kwired]

I was thinking why would hand rails at top of a 10 meter diving platform need to be bonded, and still question whether they really do need to be bonded, but wording in exception 3 of 680.26 (B)(7) kind of says they intend to include such a thing.

Exception No. 3: Those greater than 3.7 m (12 ft) measured vertically above the maximum water level of the pool, or as measured vertically above any observation stands, towers, or platforms, or any diving structures, shall not be required to be bonded.

 

[Sconnie]

I was thinking why would hand rails at top of a 10 meter diving platform need to be bonded, and still question whether they really do need to be bonded, but wording in exception 3 of 680.26 (B)(7) kind of says they intend to include such a thing.

The hand rails start at the first step from the pool deck, then end at the top of the first 5 meter platform. There is a railing around the 5 meter platform and the next set of hand rails start at the stairs to the 7.5 meter platform and so on. I read exception 3 as we can stop bonding these parts past 12' above the water level. Which means once we bond the first set of hand rails that ends at 16' we should be good. Thoughts?

 

[kwired]

The hand rails start at the first step from the pool deck, then end at the top of the first 5 meter platform. There is a railing around the 5 meter platform and the next set of hand rails start at the stairs to the 7.5 meter platform and so on. I read exception 3 as we can stop bonding these parts past 12' above the water level. Which means once we bond the first set of hand rails that ends at 16' we should be good. Thoughts?

Not how I read that exception. It says 12' above water level "or" (12') above mentioned items.

Railing would have to be 12' above the diving platform before you don't have to bond it per this exception. Had they not specifically mentioned what they did in this exception, I don't know there is any other wording that would have required hand rail at the top of the platform to be bonded. Bottom would be required to be bonded if any part is within 5 feet of the inside walls of the pool. If rail is electrically continuous to the top additional bonding shouldn't be necessary. I don't see that concrete structure of the platform is required to be bonded, just a concrete pool shell and perimeter surfaces. Unless base of concrete structure is within 3 feet of the inside wall of pool it is outside that perimeter surfaces zone.

 

[Sconnie]

Not how I read that exception. It says 12' above water level "or" (12') above mentioned items.

Railing would have to be 12' above the diving platform before you don't have to bond it per this exception. Had they not specifically mentioned what they did in this exception, I don't know there is any other wording that would have required hand rail at the top of the platform to be bonded. Bottom would be required to be bonded if any part is within 5 feet of the inside walls of the pool. If rail is electrically continuous to the top additional bonding shouldn't be necessary. I don't see that concrete structure of the platform is required to be bonded, just a concrete pool shell and perimeter surfaces. Unless base of concrete structure is within 3 feet of the inside wall of pool it is outside that perimeter surfaces zone.

Got it, I reread and agree. Thanks for the input.