Rooftop inaccessible to unqualified persons? 1000V equipment

[CodeQuandary]

Is a rooftop an "inaccessible to unqualified persons" location? This is concerning a 1000V DC PV installation, but since this is really a more general NEC question I'm posting it here. The related equipment for the most part (inverters etc) will be on the roof, with the modules. There is no roof deck or other ready/general access. Every time I consider it I switch sides ;-)

It is certainly not readily accessible (to anyone), but once a roofer is up there, for example, they could walk right up to it.
See, now it's bugging me further: if it IS deemed "accessible to an unqualified person" (and therefore needs to be fenced/guarded), then it seems like ALL the wiring for the modules would have to be put in raceways or otherwise made inaccessible (i.e. Solarscrim www.solarscrim.com -- would that suffice? Hmm, no obvious listings...). I've never seen something like this used before, but we haven't had 1000V PV systems here yet, which is probably where it would be used (ok, that IS a PV forum question...).

Thanks for any help!

 

[north star]

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CodeQuandary,

Which applicable Building Code edition are you using to determine
the definition of "accessible to unqualified persons", or "non-accessible
to qualified persons" ?


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[mgookin]

What can you tell us about the roof?
How high?
How does one get up there?
Does it require a key to get there?

 

[north star]

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There is this from the `12 IMC:

306.5 Equipment and appliances on roofs or elevated structures:
"Where equipment requiring access or appliances are located on an elevated structure
or the roof of a building such that personnel will have to climb higher than 16 feet
(4877 mm) above grade to access such equipment or appliances, an interior or
exterior means of access shall be provided.........Such access shall not require
climbing over obstructions greater than 30 inches (762 mm) in height or walking
on roofs having a slope greater than 4 units vertical in 12 units horizontal (33-percent
slope)................Such access shall not require the use of portable ladders......Where
access involves climbing over parapet walls, the height shall be measured to the top
of the parapet wall.

Permanent ladders installed to provide the required access shall comply with the
following minimum design criteria:
1. The side railing shall extend above the parapet or roof edge not less than 30
inches (762 mm).2. Ladders shall have rung spacing not to exceed 14 inches (356 mm) on center.
The uppermost rung shall be a maximum of 24 inches (610 mm) below the upper
edge of the roof hatch, roof or parapet, as applicable.
3. Ladders shall have a toe spacing not less than 6 inches (152 mm) deep.
4. There shall be a minimum of 18 inches (457 mm) between rails.
5. Rungs shall have a minimum 0.75-inch (19 mm) diameter and be capable of
withstanding a 300-pound (136.1kg) load.
6. Ladders over 30 feet (9144 mm) in height shall be provided with offset
sections and landings capable of withstanding 100 pounds per square foot
(488.2 kg/m²). Landing dimensions shall be not less than 18 inches (457 mm)
and not less than the width of the ladder served............A guard rail shall be
provided on all open sides of the landing.
7. Climbing clearance..........The distance from the centerline of the rungs
to the nearest permanent object on the climbing side of the ladder shall be
a minimum of 30 inches (762 mm) measured perpendicular to the rungs.
This distance shall be maintained from the point of ladder access to the
bottom of the roof hatch.........A minimum clear width of 15-inches (381
mm) shall be provided on both sides of the ladder measured from the
midpoint of and parallel with the rungs except where cages or wells are
installed.
8. Landing required. The ladder shall be provided with a clear and
unobstructed bottom landing area having a minimum dimension of 30
inches (762 mm) by 30 inches (762 mm) centered in front of the ladder.
9. Ladders shall be protected against corrosion by approved means.
10. Access to ladders shall be provided at all times.

Catwalks installed to provide the required access shall be not less than
24 inches (610 mm) wide and shall have railings as required for service
platforms.

Exception: This section shall not apply to Group R-3 occupancies.

306.5.1 Sloped roofs:
Where appliances, equipment, fans or other components that require
service are installed on a roof having a slope of three units vertical in
12 units horizontal (25-percent slope) or greater and having an edge
more than 30 inches (762 mm) above grade at such edge, a level
platform shall be provided on each side of the appliance or equipment
to which access is required for service, repair or maintenance.......The
platform shall be not less than 30 inches (762 mm) in any dimension
and shall be provided with guards...........The guards shall extend not
less than 42 inches (1067 mm) above the platform, shall be constructed
so as to prevent the passage of a 21-inch diameter (533 mm) sphere and
shall comply with the loading requirements for guards specified in the
International Building Code............Access shall not require walking
on roofs having a slope greater than four units vertical in 12 units
horizontal (33-percent slope)............Where access involves
obstructions greater than 30 inches (762 mm) in height, such
obstructions shall be provided with ladders installed in accordance
with Section 306.5 or stairs installed in accordance with the
requirements specified in the International Building Code in the path
of travel to and from appliances, fans or equipment requiring service."



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[mpoulton]

I recall having an "inaccessible to unqualified persons" debate with an inspector several years ago on a different issue. The inspector's interpretation (which we ultimately accepted) was that something is not inaccessible to unqualified persons if any unqualified staff have a way to access it without REALLY going out of their way and breaking the rules. If any unqualified staff can access the area, then it fails. Keys held only by qualified staff (not stored on a key rack in facilities with all the other keys), together with posted signage, were considered adequate. I don't think most rooftops would qualify.

 

[ggunn]

I recall having an "inaccessible to unqualified persons" debate with an inspector several years ago on a different issue. The inspector's interpretation (which we ultimately accepted) was that something is not inaccessible to unqualified persons if any unqualified staff have a way to access it without REALLY going out of their way and breaking the rules. If any unqualified staff can access the area, then it fails. Keys held only by qualified staff (not stored on a key rack in facilities with all the other keys), together with posted signage, were considered adequate. I don't think most rooftops would qualify.

I have put PV systems on quite a few commercial/school rooftops. All but one I can remember had hatches to the roof that locked with a padlock to which only the building custodial staff had keys. The one exception had no rooftop access from the interior of the building at all; the only way up there was with a 40' ladder. I believe all those rooftops would qualify as inaccessible to unqualified persons.

We did, however, find a sizeable stash of empty beer bottles on one of them.