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Understanding Active and Passive Floodproofing Options for Non-Residential Buildings in a Special Flood Hazard Area Course Number: SV003 Learning Units:

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Presentation on theme: "Understanding Active and Passive Floodproofing Options for Non-Residential Buildings in a Special Flood Hazard Area Course Number: SV003 Learning Units:"— Presentation transcript:

1 Understanding Active and Passive Floodproofing Options for Non-Residential Buildings in a Special Flood Hazard Area Course Number: SV003 Learning Units: 1 Credit Designation: HSW Provider: Smart Vent Products, Inc Provider number: T058

2 Learning Objectives Identify the applicable ICC building codes and FEMA regulations pertaining to non-residential floodproofing options. Understand the design benefits for each dry floodproofing and wet floodproofing option. Identify design issues and occupants risks associated with active flood proofing techniques and the liability associated with those risks. Analyze the difference between Active and Passive floodproofing techniques and how they affect the buildings sustainability.

3 Course Outline Section 1 General Overview Section 2 Dry Floodproofing
Effects of hydrostatic pressure NFIP (FEMA) Regulations, ICC building codes, ASCE standards Define dry and wet floodproofing techniques Active and passive methods Section 2 Dry Floodproofing Planning considerations & engineering requirements Active vs Passive methods FEMA floodproofing certificate Designer Liability Section 3 Wet Floodproofing Options Engineered vs non-engineered ICC-ES Evaluated Products Project Studies

4 Section 1 Section 1 Effects of hydrostatic pressure
NFIP (FEMA) Regulations, ICC building codes, ASCE standards Define dry and wet floodproofing techniques Active and passive methods

5 Hydrostatic Pressure What we are mitigating against in floodplains is hydrostatic pressure. This is the force that water at rest exerts on any submerged object

6 The Effects of Hydrostatic Force
B A, B, C, and D photos show different types of damage that has occurred to foundation walls from hydrostatic pressure. Action Photo A shows a wall that caved in due to excessive pressure on the outside of the wall. The pressure was not equalized with water on the inside of the structure. (Outside Lateral Force) Action Photo B shows a wall that exploded out due too excessive pressure on the inside. Water got into the foundation on the rising flood, but could not get out quickly enough on the recede to equalize pressure. This illustrates the importance of bi-directional venting. (Inside Lateral Force) Action Photo C illustrates the effect of vertical or buoyancy forces on a structure. This home was lifted off of its’ slab and dropped in the middle of the street as the flood receded. (Vertical Force) For dry floodproofing designs careful attention must be given to resisting buoyancy, designs should include helical anchors. Action Photo D shows shearing of a block foundation wall from floodwater, another example of vertical forces. Home was lifted up off of the foundation and floated in place. When the house settled back down on the foundation the top block was shifted off of the next course of blocks by 1.5+ inches. The top course of block was properly bonded to the sill plate. C D

7 Floodproofing Options: A Zones
Dry Flood Proofing Wet Flood Proofing Non-Residential Dry Floodproofing to “resist” Wet Floodproofing to “relieve”

8 Dry Floodproofing (Resist)
Making a building watertight, impermeable to flood waters NFIP allows in non-residential buildings only For new construction or substantial improvements to existing buildings Acceptable in A, AE, A1-A30, AO, & AH Zones Design must be certified (Liability) FEMA’s requirements for Non-Residential floodproofing are found in Technical Bulletin 3-93 Dry floodproofing is not permitted in residential structures Allows the design to have a lowest floor below the BFE provided that the building has been designed, constructed and certified to be floodproofed Not allowed in Coastal Hazard Areas, Zone V, VE, or V1-V30 Dry-floodproofing certificate discussed in a upcoming slide

9 Wet Floodproofing (Relieve)
Flood Vents equalize the hydrostatic pressure NFIP allows in both residential and non-residential structures For new construction or substantial improvements to existing buildings Acceptable in A, AE, A1-A30, AO, & AH Zones ICC-ES Certified Options The wet floodproofing requirements are found in FEMA’s Technical Bulletin 1-08

10 Additional Floodplain Construction References
2009 IBC ASCE 24-05 IBC: structural design chapter 16 Section Flood Design Data. For buildings located in a flood hazard area’s per section the design must meet section requirements. requires that: (Design Plan Example in Next Slide) The design plans show the elevation of the proposed lowest floor, including the basement. The elevation to which any nonresidential building will be dry flood proofed In V-Zones show the elevation of the bottom of the lowest horizontal structural member of the lowest floor. IBC states how you will identify if a construction lot is in a floodplain. states that it’s the municipalities responsibility to adopt flood hazard maps, these maps will show the special flood hazard areas for the community. These SFHA’s areas were identified by FEMA during a “Flood Insurance Study” which are also identified on a FIRM. The design documentation requirements: Must be prepared and sealed by a registered design professional and submitted to the community official for approval. 1.1 For A-Zones you must document the lowest flood elevation, 1.2 State the use of flood openings (references to ASCE 24) discuss attaching our ICC-ES report, 1.3 if you opt to use dry-floodproofing measures you must certify that the design is in compliance with ASCE 24 a FEMA floodproofing cert is also required. ASCE 24-05 Dry & Wet Floodproofing requirements.

11 Design Plans The pictured drawing shows the first floor elevation and the 100 year floodplain elevation. The blue area identifies the floodplain all the way through the building. 2 foot of freeboard was designed in. This project utilized flood vents

12 Which To Design With? Dry Vs Wet Design differences and costs
Active vs Passive approaches Choosing the right floodproofing measure for the design.

13 Section 2 Dry Floodproofing Design requirements & materials
Active & passive flood barriers Flood proofing certificate & liability

14 Dry Floodproofing Planning: Is it possible? Considerations
Warning time, Safety & Access Flood Velocities, Depths, and Debris Frequency Emergency Plan Inspection & Maintenance Plan Cost Liability Things to consider before jumping into a dry floodproofing design careful study of the site and the following factors must take place to see if dry floodproofing is appropriate. if the site will be surrounded by rapidly rising, high velocity flood waters and the warning time is short then the site is not suitable for a dry floodproof design.

15 Warning Time, Safety & Access
Time is critical Active flood proofing measures Human Stability Dry Flood Proofing is not appropriate in a flash flood area. Page 3 TB-3 *Warning Time, Safety & Access to the building is the first consideration for your design. You must review the rate of rise of the floodwaters for the site in questioned to determine how much time there will be to evacuate a building and how much time to install dry floodproofing measures such as flood shields and gates, close valves, etc (Actions 1 & 2) Time is critical because floodwater can sneak up on you and you need to allow enough time for people to safely exist the building. The design needs to be sound and exists for the building should not be under water. Back in 1987 Colorado State University conducted a study on human stability in a flood flow, if the base flood product number is 4 or greater (depth in feet multiplied by velocity in feet per second) it will create a hazard for anyone attempting to escape from or gain access to the site. (Action 3 & 4) Big issue with Active dry floodproofing products (Requiring Human Intervention) is the need for people to be present before the flood to install the devises to protect the building. Man power is needed to install the pictured floodproofing shields, time is also needed to get these barriers in place, putting people at risk. Do not use dry floodproofing measures in a flash flood area.

16 Flood Velocities, Depths & Debris
Cost Prohibitive When Flood Velocities are over 5 feet per second Base Flood depths in excess of 3 feet Impact forces from debris Calculation assumes 1 second duration of impact Object estimated at 1,000 pounds Second step considerations. If the flood velocities are in excess of 5 feet per second or the flood depths of the water are shown to exceed 3 feet during a base flood then dry floodproofing becomes cost prohibitive. In a upcoming a slide while discussing minimum engineering requirements we will show a chart regarding water depth and the hydrostatic pressures you need to account for in your designs. (First Action) You can pull the food velocity for a area by referencing the cross section on a communities FIS. From here you will only be able to see the velocities in the floodway, the Floodway mean velocity will yield the highest velocity number for the floodplain.  If you wanted site specific velocities, you would get a copy of the modeling in HEC-RAS and look at the cross section with the velocity distribution. (Image included as first action) What is a FIS?A Flood Insurance Study (FIS) is a book that contains information regarding flooding in a community and is developed in conjunction with the Flood Insurance Rate Map (FIRM). The FIS, also known as a flood elevation study, frequently contains a narrative of the flood history of a community and discusses the engineering methods used to develop the FIRMs. The study also contains flood profiles for studied flooding sources and can be used to determine Base Flood Elevations for some areas.  (Second Action) Page 4 Because of the additional risks of dry flood proofing, a 1 foot freeboard must be designed in for all dry floodproofing measures. All though for floodplain management purposes the structures floodproofing only needs to meet the BFE, for the increased risk the NFIP subtracts 1 foot from the elevation. So if the building is only dry flood proofed to the BFE the NFIP will rated as if its 1 foot below BFE with its floodproofing protection. In these cases the flood insurance rate will be extremely high. Additional freeboard may be required by local ordinance, which will require additional material costs.

17 Flood Frequency How often Wear & Tear
Risks of implementing a emergency plan over and over If frequency is not a factor, time to design Pg 4 Tb-3 Last check point before moving a head with a dry floodproof design is flood frequency. If the area floods frequently it can cause wear and tear on a structures external components and can compromise the structural integrity of the building. There are also risks of implementing a emergency operation plan over and over. To determine flood frequency you can refer to USGS and other references for analysis on flood frequency. (River) To better understand frequencies of flooding, depths and velocities you can work with a engineering firm that specializes in hydrology Hydrology is the study of the movement, distribution, and quality of water A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil and environmental engineering. John A. Miller, P.E.*, CFM, CSM Water Resources Engineer Certified Floodplain and Stormwater Manager Princeton Hydro, LLC 1108 Old York Road Suite 1, PO Box 720 Ringoes, New Jersey t x110 c f 
 If warning time, safety & access, flood velocities & Depths, and flood frequency is not a issue then dry flood proofing is a option.

18 Emergency Operation Plan
Establish the chain of command & responsibilities Procedure for notifying necessary parties A list of specific duties & location of all dry floodproofing materials Evacuation plan- with and without duties Annual training drills with community officials Pg 4 & 5 of TB3 Design Professional must produce the plan The emergency operation plan is critical when flood proofing requires human intervention. The plan is required to ensure that the floodproofing components will operate properly under all conditions, including a power failure which is often seen during floods. A continuous source of electricity will be needed to ensure that sump pumps are able to operate, this will require the need for a back up generator or a battery back up for the pump. Pumps are required in all dry floodproofing designs. The above listed items on the slide make up a good plan.

19 Inspection & Maintenance Plan
Mechanical equipment, sump pumps & generators Inspect & test all flood shields (check gaskets) Inspect foundation walls for cracks Levees & berms Pg 5 of TB3 Plan should take place annually at a minimum The inspection and maintenance plan should cover the above listed components. Action 1 will bring up a flood gate diagram of checkpoints. Both the emergency and and inspection plans must be submitted with the dry floodproofing certificate. Before permits are granted the community official should require the property owner to sign an agreement stating that the plan will be adhered to. The agreement will also include language regarding change of ownership. And any lease agreements will contain lease holders responsibilities for the floodproofed building.

20 Dry Floodproofing Certificate
Property Address Section I: FIRM info Section II: Flood proofing design info Section III: Certification Pgs 10 – 12 TB-3

21 Property Address Building Location and ownership info

22 Section I & II Section I: is for the Flood Insurance Rate Map info. This includes the FIRM Flood Zone and the BFE Section II: is to document the elevation the building was flood proofed to. Make mention of the “note” regarding being at least 1 foot higher then the BFE with the dry floodproofing measure to receive rating credit.

23 Section III Section III: This is the actual certification of the form as required by Section 60.3 of the NFIP regulations. The design professional signing this form are certifying that they have developed and or reviewed the design plans and specifications and find them in compliance with accepted construction standards of practice for dry floodproofing.

24 Floodplain Impact Consideration
Increased flood depths, velocities, & flows Growing the floodplain ASFPM: No Adverse Impact The action of one property owner or community does not adversely affect another One last consideration, how will the design affect the floodplain? ASFPM: Mission Statement (Goal) to prevent the growth of the floodplain.

25 Section 3 Wet Floodproofing (Passive Solution)
Engineered vs Non-engineered ICC-ES Evaluated Products Proper Placement Wet floodproofing is less impactful to the over all floodplain as we are elevating and letting the water take its natural course.

26 Three Options ICC-ES Certified Engineered Openings
Unique project specific Engineered Openings Non-engineered Openings Both FEMA and the ICC reference ASCE 24. ASCE requires that flood openings allow for a 3” sphere to pass through to permit for debris. Everyone at this point should put away TB-3 and pull out TB-1 to following along. These are the three flood venting options, we will review reverse order.

27 3. Non-engineered Openings
Provide 1 sq in of net open area for every 1sq ft of enclosed area An 8”x16” hole with air vent device inserted does NOT provide 128 sq in! Account for obstructions to flow If I-Codes apply, 3” min dimension Liability: Design Professional, Surveyor, Construction Official #3 option Going from worst to first Non-engineered openings meet the method of 1 net sq/in of flood venting for every 1 sq/ft of enclosed area. Air vents are the most popular non-engineered openings These openings are not designed as flood openings 27

28 Unacceptable Measures: Page 19 TB-1
Standard foundation air ventilation devices that can be closed manually, unless they are disabled in the open position On page 19 of TB-1 FEMA states certain measures that will not be acceptable as flood openings. The main reason that windows, garage doors and exterior doors do not qualify as flood openings, is because human intervention is required to open them.

29 Unacceptable Measures: Page 19 TB-1
Standard foundation air ventilation devices that are designed to open and close based on temperature

30 Unacceptable Measures: Page 19 TB-1
Windows below the BFE Garage Doors without openings installed in them Standard exterior doors without openings installed in them

31 Debris is a Fact of Flood
ASCE 24 is referenced in both FEMA regulations and the International Building Codes. It requires a 3” diameter sphere to pass through the flood opening for it to comply. This is to ensure that grills and louvers do not interfere with the passage of debris. 31

32 3” Clarification The question asked of the ICC in by Licensed Design Professional. Item of section R requires that the flood opening “shall be at least 3 inches in diameter” Does this mean that the opening must have a minimum diameter of 3 inches? Response is blown up in the slide.

33 2. Unique Engineered Openings
Designed for a specific project Certified based on computations (TB1 and ASCE 24) I-Codes & ASCE 24: 3” min dimension Not for mass distributed products Design must be accompanied by the original certification Liability: Licensed Design Professional # 2 option This option is available for a licensed design professional choosing to design a engineered opening to meet specific project needs, such as aesthetic reasons.

34 Unique Engineered Opening Certificate
Statement certifying the openings will automatically equalize hydrostatic flood loads Range of flood characteristics used Installation requirements Property address (must be licensed in that state) Licensed design professionals name, title, address, type of license, license number, state in which the license was issued If the unique (project specific) engineered opening method is used the original engineered opening certificate must include the following. Today there are a couple companies currently miss using this option and making photo copies of certificates for their air vents. Designers should be very careful of these products if they are requested to be used as a “equivalent” substitution to a ICC-ES certified engineered opening. Don’t believe everything you read online.

35 1. ICC-ES Engineered Openings
Designed, Tested, & Certified for performance Designed and certified based on computations (TB1 and ASCE 24) ICC-ES Certifed: AC-364 (AFFV) I-Codes & ASCE 24: 3” min dimension The #1 option for any design should be performance tested products to ensure they will operate probably when called upon. The ICC-ES has established testing criteria for Automatic Foundation Flood Vents (AFFV) Action: Debris is part of the testing criteria, it includes in dried leaves, grass clippings and 3 inch balls. All are included to prove that the vent will not clog with debris during a flood which would leave the vent ineffective relieving hydrostatic pressure and the foundation at risk. The Evaluation Service is a subsidiary of the International Code Council.

36 ICC-ES Report Reference the ICC-ES report in the catalog
Reports Lists: Name of manufacturer, different models offered, and the square feet each model is certified to cover. Action: All products certified through the ICC-ES will be clearly identified in the field with a label with the model number and certified coverage.

37 Liability For Performance
Rests on the manufacturer’s shoulders Each vent is tested Regular QA inspections The next few pictures are of our Anderson, SC manufacturing plant. All of our products are constructed out of 316 Marine Grade stainless steel, and are made in the USA!

38 Placement Requirements
With in one foot (12”) of the adjacent grade. 1 foot is the max.

39 Placement Requirements
FEMA Photo In this example the vents are with in 12” of the inside grade which was higher then the outside grade for each opening. If your design will have this type of application where the vents are higher then 12” of the outside grade but in compliance with the interior make sure this is noted on the plans, and the surveyor is alerted to measure from the inside.

40 Placement Requirements
Vents on two different walls. Discuss that each enclosed area below the BFE must have at least two flood opening, and must be on two different walls. Internal enclosed spaces with in a larger space must also meet the same. Explain the use of flow throw openings on dividing walls to join the spaces. 40

41 Sloping Sites: Walk Out Basements
The interior floor along the lower side of a building that is set into a sloping site must be at or above the exterior grade across the entire length of the wall. If the exterior grade was not level or lower with the interior grade on one complete side, then the enclosed area would be classified as basement Diagram 2 on the elevation certificate this would result in a higher insurance premium. In the above example it is important to also point out that most of the vents should be placed in the lower wall as it will be the wall that needs to relieve hydrostatic loads first. Openings in this wall will also allow for the best drainage. 41

42 Dry vs Wet William L. Coulbourne, P.E. Floodproofing Report
Dry vs Wet Floodproofing Technologies Two dry scenarios Two wet scenarios 5,000 sq. ft. spaces 4 foot BFE with 1 foot freeboard

43 Dry Scenario 1D 5,000 sq. ft. full height enclosed space
1D includes a 5000 sq/ft full height enclosed space with a concrete slab and poured concrete walls to resist water. Two 12 foot wide garage doors, needed bolt-in-place (Active) flood barriers Two 3 foot wide entry doors, needed bolt-in-place flood barriers Walls need to be coated with a water proof membrane to prevent water leakage Resistance to buoyancy is significant for 5 ft. of water depth, helical anchors were required to prevent floatation. 60,000 pounds of uplift resistance per

44 Dry Scenario 2D 5,000 sq. ft. crawlspace
2D is for a 5,000 sq/ft crawl space. No garage doors or entry doors, only two crawlspace doors.

45 Wet Scenario 1W 5,000 sq. ft. full height enclosed space
(13) ICC-ES certified flood vents (13) Smart Vent 16x16 model flood vents were utilized. Each is certified to cover 400 sq. ft. each. No reinforced concrete, no helical anchors

46 Wet Scenario 2W 5,000 sq. ft. crawlspace
(13) ICC-ES certified flood vents (13) Smart Vent 16x16 model flood vents were utilized. Each is certified to cover 400 sq. ft. each. No reinforced concrete, no helical anchors

47 Cost Analysis 1D vs 1W: Wet is 53% ($48,157) less then Dry and no liability associated with the flood proofing measure. 2D vs 2W: Wet is 67% ($50,877) less then Dry and no liability associated with the flood proofing measure.

48 Summary: Considerations
Local floodplain ordinances Health, Safety & Welfare of the Occupants Active vs Passive techniques Costs Liability SFHA Non-residential design considerations summary, things to think through before choosing between Dry and Wet floodproofing measures.

49 Questions

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