HomeMy WebLinkAboutMurar Engineering & Design Inc. MURAR
IP' ENGINEERING
& DESIGN INC II
February 4,2014
Neil Erickson
Hawaii County Public Works—Building Division
Aupuni Center, 101 Pauahi Street, Suite 7
Hilo, HI 96720
Re: SunEarth SolarStrut Approval for Hawaii County—Revision for inclusion of 3/8 and
5/16 bolts
Dear Mr. Erickson,
This letter is to document that I have reviewed the SunEarth SolarStrut photo voltaic racking
system and I have found that it is in accordance with the requirements for the wind and seismic
design for Hawaii County. These requirements are acceptable up to a seismic design category E
or less.
The wind design for the system is governed by the 5/16"diameter bolt that is embedded
2.875"into the wood member with a capacity of 811 lbs (The 3/8" bolt has a greater capacity).
This requirement is per Quick Mount ICC report ESR 2835. This assumes that the bolt takes less
than 18 square feet of panel area.
The effective wind speed on Hawaii County is governed by a topography factor Kzt, a wind
speed,a directionality factor Kd and a wind exposure. The directionality factor Kd is assumed to
0.75 for the worst case scenario on Hawaii County. Wind exposure in Hawaii County is either B
or C. Any exposures greater than a C will require a Structural Engineer review.
For Exposure B situations,the wind effective is 120 mph with a Kzt= 1.6 or less. Most of
Hawaii County is less than 1.6 Kzt,except for the slopes of Mauna Kea, Hualalai, Mauna Loa
and the Kohala's.
For Exposure C, the wind maps have to be consulted. The correlating Kzt(topographic Factor)
and the wind speed are listed below:
120 mph wind is limited to a Kzt= 1.1 for Exposure C
110 mph wind is limited to a Kzt= 1.3 for Exposure C
105 mph wind is limited to a Kzt= 1.45 for Exposure C
100 mph wind is limited to a Kzt= 1.55 for Exposure C
This certification is only for gable roof,hipped roof or monoslope roof structures up to 2
stories and 30 feet high,flush mount installations on the main part of the roof and not on the
eaves.
MURAR Engineering and Design INC Phone: 808-333-0999
1674 Hill Road Suite 18 Fax: 866-855-9379
Boise, ID 83702 e-mail:contact@murarengineering.com
www.MurarEngineering.com
2/4/2014 SunEarth SolarStrut
MURAR
IP' ENGINEERING
& DESIGN INC II
All systems where the panels are tilted up, and systems that fall outside the above wind
parameters, will require plans and a review by a licensed Hawaii structural engineer.
Following are typical specifications for the connections to meet the Hawaii County requirements:
Bolts: 5/16"x6"or 5/16"x8"quick mount stainless steel hanger bolts or Quick
Mount bolt per ICC report ESR 2835. The bolts will need to be
embedded 2.875"into the supporting wood members.
or
3/8"x6" or 3/8"x8" solar strut stainless steel hanger bolts or Quick
Mount bolt per ICC report ESR 2835. The bolts will need to be
embedded 3 1/4"into the supporting wood members.
Attachment Spacing: 4'-0"on center maximum for a 1 5/8"tall SunEarth SolarStrut
6'-0"on center maximum for a 2 1/2"tall SunEarth SolarStrut
Cantilever: 20"for 2'-0"back span(1 5/8"or 2 1/2" SunEarth SolarStrut)
25"for 3'-0"back span(1 5/8"or 2 1/2" SunEarth SolarStrut)
30"for 4'-0"back span(1 5/8"or 2 1/2" SunEarth SolarStrut)
35"for 5'-0"back span(2 1/2" SunEarth SolarStrut)
40"for 6'-0"back span(2 1/2" SunEarth SolarStrut)
Clearance: 1"to 2"clear from top of roof to bottom of strut
This letter is to certify the mounting structure to the roof rafters or trusses in the roof system. The
requirements of the overall structure need to be in compliance with the Hawaii County document
"Steps for a residential photovoltaic (PV) system". If the roof structure or any other structural
components of the structure do not comply with the Hawaii County document or this document,
then the installation documents will need to be verified by a licensed Hawaii structural engineer.
This document supersedes all other documents. `Z`P oAPRo Us
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Please contact me if you require further information. xp
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30/14
Regards, PE 10704 S
Kevin Murar,PE, SE
Murar Engineering and Design, Inc
MURAR Engineering and Design INC Phone: 808-333-0999
1674 Hill Road Suite 18 Fax: 866-855-9379
Boise, ID 83702 e-mail:contact@murarengineering.com
www.MurarEngineering.com
2/4/2014 SunEarth SolarStrut