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CONSTRUCTION
CGCO13084
' CORPORATION
CCC053853
August 186, 2021
We do more than building bui;b1imons.
we're building
Internet: www.rkdavis.com
Mr. Andrew Manero
Plans Examiner
St. Lucie County Building Department
2300 Virginia Avenue
Fort Pierce, FL 4982
Re: PUntil#,2+1t07=0635
Gehl &7GrmFd'mg oms with Ventilation
Dear Andrew:
AUG � 0 2w
St. Permitttinry
9 u�
The following responses are offered to your plans review comments for the project referenced above:
1) No Electric documents received. Please provide documents for review. Electrical feeders,
disconnects, control wiring, etc. for the ventilation equipment and lighting within the Gel & Grinding
Rooms has been included on the Main Building Permit construction documents (Permit # 2105-0262).
Additionally, all fire alarm devices for fan shut -down of ventilation equipment have been shown on the
Main Building's fire alarm construction drawings.
>m-2) Please provide updated plan set to meet the requirements of the Mechanical FBC 71 Edition 2020.
Sheet V-8, Supply and Exhaust Duct construction specifications show ICC Building Code, Mechanical
2009 Edition. May have additional comments upon review ofthe updated plan set. Please see our updated
page V-8 with the correct Mechanical Code shown in the notes. All other plan pages are correct as
submitted.
3) No documents provided for the actual Room/Booth. Three (3) copies of the Gel & Grinding
Room fabrication and installation shop drawings are attached to this response letter.
Thank you for your comments. Please feel free to contact us should there be further comments or needs for
additional information.
rect
erely,
es
Manager
77rCWAW7
4
5.1 * Spray Areas.
5. 1.1 Walls, doors, and ceilings that intersect or enclose a
spray area shall be both of the folloNving:
(1) Constructed of noncombustible or limited-combusLible
materials or assemblies
(2) Securely and rigidly mounted or fastened
I
5.1.1.1 The interior surfaces of the spray area shall be smooth,
designed and installed to prevent pockets that can trap resi-
dues, and designed to facilitate ventilation and cleaning.
5.1.1.2 Air intake filters that are a part of a wall or ceiling
assembly shall be listed in accordance ivith UL 900, Air Filter
uIrlits.
5.1.2 The floor of the spray area shall be constructed of
noncombustible material, limited -combustible material, or
combustible material that is completely covered by noncombus-
tible material.
5.1.3 Aluminum shall not be used for structural support
members, walls, or ceilings that enclose a spray area or for
ventilation ductwork to or from an enclosed spray area unless
otherwise permitted by 5.1.3.1.
5.1.3.1 Aluminum shall be permitted to be used for interior
components, such as platforms, spray apparatus components,
and other ancillary devices.
5.1.4 Enclosed spray areas shall be provided with means of
egress that meet the applicable requirements of Chapter 40 of
NSA 101.
Cha ter 17 Styrene Cross -Linked Composites Manufacturing
Ip
(Glass Fiber —Reinforced Plastics)
17.1* Scope. This chapter shall apply to manufacturing
processes involving spry application of styrene crass linked
thermoset resins (commonly luiourn as glass fiber —reinforced
plastics) for hand lay up or spray fabrication methods, that is,
resin application areas, and where the processes do not
produce vapors that exceed 2.5 percent of the lourer flammable
limiL
17.2 Resin Application Equiipmen . L The equipment and appa-
ratus for spiny application of the resin shall be installed and
used in accordance Nith the requirements of CAiapter 16 and
Chapter 17.
17.3* Fire Protection. Resin application areas shall be protec-
ted in accordance N%i.th Chapter 9.
17.4 Resin Storage. The quantity of ig-nitible (flammable and
combustible) liquids located in the vicinity of resin application
areas outside an inside storage room or storage cabinet in e-my
one process area shall not exceed the greater of any of the
Mowing:
(1) A supply for one day
(2) The sum of 95 L (25 gal) of Class IA' [FP < 22.8*C, (73'F)
and BP < 37.8'C (100'F) I liquids in containers and 454 L
(1.20 gal) of Class IB, IC, U, or 1H [any flash point and. BP
> 37.8*C (100'F) ] liquids in containers
(3) 0 ne approved portable tank not exceeding 2500 L
(660 gal) of Class IB, IC, H, or III (any flash point and BP
> 37.8*C (100'F)] liquids
17.5 Electrical and Other Hazards.
17.5.1 Electrical uiring and utilization equipment located hi
resin application areas that is not subject. to deposits of combus-
tible residues shall be installed hi accordance with the require-
nients of NIPA70 for Ordinary Hazard locations.
17.5.2 Electrical wiring and utilization equipment located in
resin application areas that is subject to deposits of combustible
residues, shall be listed, for such expos-ure and shall. be suitable
cmucrs, venwauon raps, spray appucauon equ prnenc, worm-
pieces or containers that receive the spray stream., and piping
that conveys ignitible (flammable or combustible) liquids shall
be electrically grounded.
17.5.4 Space heating appliances or other hot surfaces in resin
application areas shall not be located urliere deposits or resi-
dues accumulate.
17.6 Ventilation.
17.6.1 Mechanical ventilation shalll be designed amid installed
throughout the resin application area in accordance with the
requirements of Chapter 7.
17.6.1.1 Buildings that are not enclosed for at least, three-
quarters of their perimeter shall not be required to meet this
requirement.
17.6.2 Focal ventilation shall be provided where personnel are
under or inside of, the workpiece being fabricated.
17.7 Use and Handling.
17.7.1 The storage and use of organic peroxide formi-dations
shall meet the requirements of Chapter 16.
17.7.2 Containers.
17.7.2.1 Excess catalyzed resin, while still in the liquid state,
shall be drained into a steel contail.-er of no more than. 208 L
(55 gal) capacity.
17.7.2.2 The container shall conform. to all of the following.
(1) Be located in an area with sprinklers if inside the building
(2) Be allowed to be no more than 75 percent full
(3) Dept covered (but not sealed) except when adding or
mixing material
17.7.3 1n areas where chopper g-mis are used, paper, polyethy-
lene film, or similar material shall be provided to cover the
exposed surfaces of the walls and floor to allow the buildup of
overchop to be removed.
17.7.3.1 Accu.m-nulated overchop shall. be disposed of when it
ha-q renr_herl in iveracre rhirkne3_--_q o 50 n-im l2 its_'_
DUST HAZARD ANAYLSIS REVIEW SUMMARY
11/14/2016
We recently received the results of the dust test of Ventilation Solutions fiberglass dust performed by
Exponent. Please find the attached testing results for MEC, Pmax, and MIE.
The other results are very similar to the initial results of the original dust test. While this dust can be an
explosion hazard if it is under specific conditions only, these conditions are addressed in the test results.
The dust control booth is designed as a dilution system. The booth region where grinding and trim
operations are producing material concentrations suspended in the air does not impose a deflagration
hazard as part of the booth ventilation design. [8.2.5]
1. There is no potential ignition source in the booth.
2. The booth has a bonding and grounding system.
3. The MEC of the dust will not be met if proper housekeeping procedures are followed in
accordance with NFPA 652 Sec. 8.4. This includes vacuum cleaning [8.4.2.2] and compressed air
blow down methods of cleaning. [8.4.2.6] The Facility must establish and maintain housekeeping
procedures where the fugitive emissions do not approach the MEC and the housekeeping
schedule does not allow settled dust accumulations to exceed the threshold housekeeping dust
accumulation limits.
Per NFPA 652 Sec A.5.2 — A Dust Explosion requires the following five conditions:
1. A combustible dust sufficiently small enough to burn rapidly and propagate flame.
2. A suspended cloud at a concentration greater than the minimum explosion concentration.
3. Confinement of the dust cloud by an enclosure or partial enclosure.
4. The atmosphere to support combustion.
5. An ignition source of adequate energy or temperature to ignite the dust cloud.
According to the test results from the second test with the lower Kst, the MEC of the sample was
55g/m3. So if you take the dimension of the filter areas of each booth the calculations would be as
follows:
Deck Booth:
Filter Area -
3'4"x 10'H x65' 8" = 2,188.68 ft3 = 61.97 m3
According to test results the Minimum Explosive Concentration is 55g/m3so to reach that concentration
in the filter area we would need to be
55 g/max 61.97 m3= 3,408.35g of dust required to meet Minimum Explosive Concentration.
'r
3,408.35 g = 7.514 Ibs of dust that would need to be suspended in cloud form to be ignited by the 2.5 W
ignition sources or a 450° C temperature that were used in the laboratory test.
Hull Booth:
Filter Area -
2'8"x12'Hx65'8"=2,103.97ft3=59.58m3
Accordingto test results the Minimum Explosive Concentration is 55g/m3so to reach that concentration
in the filter area we would need to be
55 g/max 59.58 m3= 3,276.9 g of dust required to meet Minimum Explosive Concentration.
3,276.9 g- 7.22 Ibs of dust that would need to be suspended in cloud form to be ignited by the 2.5 kJ
ignition sources or a 4500 C temperature that were used in the laboratory test.
These concentrations will be impossible to reach under proper operation and housekeeping of the
booth. Scheduled Housekeeping effectively with auditing and documentation in accordance with
frequency and accumulation goals established in [8.4.6.1].
NFPA promotes awareness of the three following fundamental principles:
1. Controlling the fuel (Dust is diluted and kept below MEC)'
2. Controlling the ignition sources (None'Present) [8.5]
3. Limiting the spread of any combustion event. (Booth contains dust from migrating into
other areas of the plant.)
This means ensuring that you are reducing the number of factors from the dust explosion pentagon and
installing the proper equipment to reduce the effects of an explosion, if one should happen.
Attached:
NFPA 652
Dust explosion pentagon
Exponent Test Results