Page 13 - North American Clean Energy November December 2015

NEC if they need to cut a hole in a roof there still needs to be a keep-out zone for irst responder guidance. improved with the proposed change to 690.12, but will only achieve

and come into contact with a module. If there is reason to get on the roof at all, it’s best to stay in the an increase in system complexity, cost, maintenance, and installer
However, they don’t need to enter the walkways and keep a safe clearance from the array. Moreover, the risk.
array if adequate space is provided on currently proposed UL standard does not verify rapid shutdown
the roof for safe egress and for roof systems will function in the event of a ire. Trusting rapid Hannes Knopf is the head of commercial business and portfolio strategy

ventilation access, which the current 10- shutdown to reliably work without taking other personal safety at SMA Solar Technology AG
foot keep-out zone provides.
measures could lead to perceived safety and complacency due to
he possible justiication for the 2017 familiarity. hus, the safety of rooftop PV systems will not be
SMA America | www.sma-america.com

NEC revisions may be moot points. Fire
service personnel indicate they likely will
not change their ireighting practices
with the implementation of the 80V limit

because it could still be hazardous inside
the array. Best practices advise them to
not open up burning roofs or even step
onto burning roofs unless it is absolutely

critical. In fact, many ireighters report
they are reluctant to go on the roof of a
burning building, particularly residential,
to punch holes for ventilation because

of the lightweight building methods and
materials used in modern construction,
which burn rapidly and can essentially
create an unsupported roof.

Because the proposed code revision
makes a case for a scenario that won’t
likely exist for irst responders, the safety
of PV installers, who spend signiicantly

more time on the project sites, must
be considered. he only way to meet
an 80V limit is by deploying module-
level power electronics of some kind.

However, with these devices, the number
of opportunities for failure increases
and statistically more failures will occur.
his will decrease the general reliability

of the system, while requiring those
tasked with operations and maintenance
to be on rooftops, swapping out failed
or worn out module-level devices for

ive, 10, or 15-plus years to come. A very
real risk comes with this increased time
on the roof and it will be installers and

service personnel exposed to a higher
potential for falls, which is a documented
dangerous situation.
According to the U.S. Bureau of Labor

Statistics, a total of 20,498 occupational
fatalities occurred in the construction
industry from 1992 - 2009. Of these
deaths, nearly one-third (6,591) were

attributed to fall injuries, with 2,163
fatalities resulting from roof falls.

“Fatalities from falls are the number one

cause of workplace deaths in construction.
We cannot tolerate workers getting killed
in residential construction when efective
means are readily available to prevent those

deaths. Almost every week, we see a worker
killed from falling of a residential roof.”
-----Dr. David Michaels, Assistant
Secretary of Labor for Occupational

Safety and Health

Even with an 80V limit, there are still
circumstances where irst responders

could be exposed to a shock hazard above
levels deemed to be safe. herefore,

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