WIND, WATER & SALT BEST PRACTICES AND CODE REQUIREMENTS FOR DESIGN IN A TROPICAL ENVIRONMENT

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1 Presents WIND, WATER & SALT BEST PRACTICES AND CODE REQUIREMENTS FOR DESIGN IN A TROPICAL ENVIRONMENT Mike Bishop, PE, LEED AP

2 DESCRIPTION Designing HVAC systems for educational facilities in Florida goes far beyond basic cooling and heating needs. Every component, inside and out, needs to be considered for how it will stand up to the harsh environment and result in systems - and a building - that are built to last. 2

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4 OBJECTIVES 1. Learn and understand the code requirements and good design practices for protecting equipment and other ancillary external elements from hurricane wind loads. 2. Learn and understand how to protect openings from water intrusion and to avoid common pitfalls that result in leakage and water damage. 4

5 OBJECTIVES 3. Learn and understand the effects of corrosion and how (and when) to use various solutions to protect against it. 4. Learn and understand the impact the tropical environment has on indoor air quality and how to ensure buildings stay positively pressurized and dry. 5

6 WIND PROTECTION OF EQUIPMENT

7 WIND PROTECTION OF EQUIPMENT Hurricane Andrew in 1992 changed the game and the codes related to building structure The enforcement of those codes related to ancillary equipment and support kicked in after the storms of (Charley, Francis, Jeanne, Wilma) 7

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9 WIND PROTECTION OF EQUIPMENT What is required to be supported? RTUs, fans, gravity hoods, piping, ductwork, refrigeration units, cooling towers, pumps, generators, tanks, screens, satellite dishes, solar cells, you name it! If a force can be exerted on it, it needs to be supported. 9

10 WIND PROTECTION OF EQUIPMENT Who is responsible (and liable)? Not the building official!!! Basic Rule: He who specifies the equipment is responsible to either design an adequate anchoring system or specify equipment with a FL Product Approval or Miami-Dade NOA (Notice of Acceptance) This is not the contractor s responsibility to work out in the field. Could be related to mechanical, electrical, or civil. 10

11 WIND PROTECTION OF EQUIPMENT What is the architect s and structural engineer s responsibility? Provide the foundation Steel reinforcement, wood blocking, structural concrete, structural housekeeping pad, parapets or screen walls Two examples Fan with NOA RTU with wind-rated curb 11

12 WIND PROTECTION OF EQUIPMENT Roof mounted fan with a Florida Product Approval No detail required just provide model number and NOA number on the drawings and a stamped copy of the NOA to the AHJ NOA will provide details for mounting on concrete, metal bar joists, or wood trusses 12

13 WIND PROTECTION OF EQUIPMENT RTU will require three things: a wind-rated curb, anchors for the unit to curb, and anchors for the curb to the structure Pro-tip Don t try to use a standard offthe-shelf curb in Florida! 13

14 WIND PROTECTION OF EQUIPMENT Curb manufacturer will provide engineered shop drawings for the first two items Some HVAC manufacturers have NOA curbs for smaller, common RTUs The third item (curb anchors to structure) will need to be specified by the engineer Provide a detail showing number and size of anchors and wind-load calcs 14

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16 WIND PROTECTION OF EQUIPMENT Code References FBC-M 2014, Wind resistance. Mechanical equipment, appliances and supports that are exposed to wind shall be designed and installed to resist the wind pressures determined in accordance with the Florida Building Code, Building. FBC 2014, Rooftop mounted equipment. All rooftop equipment and supports shall be secured to the structure in compliance with the loading requirements of Chapter 16 (High-Velocity Hurricane Zones). The use of wood sleepers shall not be permitted. ASCE 7 16

17 PROTECTING AGAINST WATER INTRUSION

18 WATER INTRUSION Fun with louvers, vents, and windows Since architects are the experts when it comes to windows, my focus will be on vents and louvers Any opening in the building envelope is a possible pathway for wind-driven rain to enter the building 18

19 WATER INTRUSION What does the code say? FBC_M 2014, Intake Opening Protection FBC_M 2014, Exhaust Opening Protection Louvers that protect air intake openings or exhaust openings in structures located in hurricane-prone regions, as defined in the Florida Building Code, Building, shall comply with AMCA Standard

20 WATER INTRUSION Ladies and Gentlemen, meet AMCA Standard , Test Method for High Velocity Wind Driven Rain Resistant Louvers Most hurricane louvers are AMCA 540 rated (Impact by windborne debris) VERY FEW are AMCA 550 rated Note that all of the state of Florida is considered part of the hurricane-prone region 20

21 WATER INTRUSION The old AMCA 500L test that was revised post-hurricane Andrew does not subject louvers to adequate wind speeds and rain amounts Bottom line: ALL louvers in the State of Florida that create an opening in the building envelope must be tested to AMCA Standard

22 WATER INTRUSION Important note There is NO official size exception Some jurisdictions will allow substitute louvers that are not AMCA 550 rated under 12 x12 Most jurisdictions will exempt dryer vents and other smaller openings (as long as they are properly supported) 22

23 WATER INTRUSION A tale of two louvers Louver 1 Mr. Everywhere Florida Product Approval Miami-Dade NOA AMCA 500L tested Fine print: Approved for use in closed structures with provisions to manage weather infiltration when combined with optional CD550 control damper. 23

24 WATER INTRUSION Louver 2 Mr. Keep-You-Dry Florida Product Approval Miami-Dade NOA AMCA 540 and 550 tested The ugliest louver known to mankind 24

25 WATER INTRUSION Fear Not! Louver #3 Mr. Florida Florida Product Approval Miami-Dade NOA AMCA 540 and 550 tested Fashionable and functional 25

26 CORROSION PROTECTION

27 CORROSION PROTECTION Why protect mechanical equipment from corrosion? Maximize life span Maintain efficiency and performance Protect against costly premature replacements Wind load protection It s code! (At least it used to be in 2004 in the residential section) 27

28 CORROSION PROTECTION FBC-M Ground-Mounted Units, Note 1 Corrosion protection. Buildings located within 3,000 feet ( mm) of the ocean should utilize nonferrous metal, stainless steel or steel with minimum G-90 hot-dip galvanized coating for equipment stands and anchors and stainless steel screws. But if that is not enough reason for you, let me show you some photos (cover your eyes if you re squeamish) 28

29 CORROSION PROTECTION THIS IS WHAT FIVE YEARS ON A CARRIBEAN ISLAND WILL DO TO YOU 29

30 CORROSION PROTECTION 30

31 CORROSION PROTECTION 31

32 CORROSION PROTECTION 32

33 CORROSION PROTECTION So we know it s bad what can we do? Two scenarios within 3000 feet of the ocean and inland Inland Provide coil coating for air-cooled equipment (factory applied is preferable) Minimize use of steel (even if it is galvanized) 33

34 CORROSION PROTECTION Ocean-Front Eliminate air-cooled equipment if possible Use water-cooled systems and SST closed circuit coolers Closed-loop ground source systems Provide SST cabinets if possible or aluminum All fasteners must be SST SST, aluminum, or fiberglass supports 34

35 CORROSION PROTECTION If air-cooled is unavoidable, specify the best coil coating option the factory will provide Provide hose bibbs for domestic water wash-down Expect no more than 5 year service life provide easy access for future replacement 35

36 INDOOR AIR QUALITY

37 INDOOR AIR QUALITY Florida and the Caribbean are two of the most difficult places on earth to air condition and maintain humidity control Competing priorities High air conditioning loads Code-required ventilation Mix in exhaust requirements Indoor / Outdoor experience Prevent condensation, mold, moisture damage, and temperature control problems 37

38 INDOOR AIR QUALITY How do you keep educational buildings cool and dry? Ventilation control Air balance Properly address indoor / outdoor spaces 38

39 INDOOR AIR QUALITY Classroom Ventilation Requirements Florida Building Code Mechanical, Table and ASHRAE 62.1 Classroom Occupancies for Ventilation: 5-8 years, 25 p / 1000 sf 9+, 35 p / 1000 sf People outdoor air rate: 10 cfm / person Area outdoor air rate: 0.12 cfm / sf 39

40 INDOOR AIR QUALITY Typical classroom 700 sf, 26 people OA = 344 cfm Cooling load requires 775 cfm supply air 44% OA is too high for normal A/C equipment! 40

41 INDOOR AIR QUALITY Common air conditioning units are designed to handle 15-20% OA max! Larger VAV systems or chilled water air handlers can be designed with coils capable of higher percentages Most effective strategy is to decouple the ventilation air treatment with regular space air conditioning Side benefit positive air balance! 41

42 INDOOR AIR QUALITY What is air balance and how is it achieved? Quite simply: Gazintas must be equal to (or slightly greater than) Gazoutas What are Gazoutas? Toilet exhaust Laundry exhaust Cooking hoods Lab hoods Other code-required exhaust 42

43 INDOOR AIR QUALITY Many exhaust sources are constantvolume (by code or design) Some are intermittent or variable volume, but you have to be careful When Gazoutas > Gazintas, hot, humid outside air has a way of finding its way into the building Air conditioning units are not designed to treat unconditioned air outside of their design parameters 43

44 INDOOR AIR QUALITY In order to achieve neutral or positive air balance, constant-volume preconditioned outside air must be introduced to the building DOAS (Dedicated Outdoor Air System) Units specially designed to cool air to 54F or lower then reheat air to neutral temperature using non-energy consuming reheat (hot gas reheat coil, energy wheel) 44

45 INDOOR AIR QUALITY How to address indoor / outdoor spaces? Scary words to a mechanical engineer Nana Walls! 45

46 INDOOR AIR QUALITY Architectural concept that presents an (almost) impossible air conditioning challenge If food preparation is taking place inside, health department will not allow it without screens or fly fans Air tunnel effect renders air conditioning useless Condensation is a huge problem around supply diffusers 46

47 INDOOR AIR QUALITY BEST solution is to disable air conditioning when doors are open Alternative is to provide ventilation only (fans, airflow from DOAS) Treat finishes as if they were in an exterior space Provide additional pre-treated outside air from DOAS for recovery times 47

48 CONTACT INFORMATION 48

49 CONTACT INFORMATION MIKE BISHOP, PE, LEED AP PHONE: EXT. 103 TIFFANY WEIMAR DIRECT: WEBSITE: 49

50 Questions? 50