Technical Bulletins Flashcards
Where are flood resistant building materials required?
Parts of building below the BFE. If nonresidential building is not elevated, floodproofing must be to one foot above the BFE.
What does NFIP call flood proof building material
Flood damage resistant material.. defined as capable of withstanding direct and prolonged contact with water up to 72 hours with no significant damage
What does significant damage mean in the context of the materials ability to be flood damage resistant
After 72 hours the only damage is cosmetic, can be repaired by cleaning sanding or re painting
NFIP Classifies material from 1-5 based on how resistant to water damage with 1-3 being unacceptable and 4-5 acceptable True or False
True
What are structural material examples
Floor stabs,beams, sub floors and framing and sheathing
What are examples of finish materials?
Coverings finishes or elements that do not provide structural support. Wall and ceiling treatments, carpets, doors, windows.
What are the main reasons that class 1-3 are unacceptable for below the BFE
Adhesives are water soluble, contains wood or paper product that dissolves, sheet type covering is rubbized and will not drying of material it covers, unstable, retain water
What is an example of material combinations that become unsuitable when used together
Vinyl on concrete is ok, but vinyl on plywood is unacceptable as vinyl must be pried off to allow wood to dry.
What might a long term consequence of exposure to flood water be
Flood borne Contaminants absorbed in material such as fuel and biological contaminants
What are fasteners examples
Bolts, screws, anchors, joist hangers, etc must be made with flood resistant materials
What are recommended fastener material
Hot dip galvanized or stainless steel especially in coastal area where airborne salts add to corrosion. Treated wood is also corrosive.
What additional flood proof rules apply to accessory structures
Construction below the BFE must be with flood mate-siesta the materials and the building must be anchored to resist flotation, collapse and lateral movement and other requirements based on the flood zone.
What is wet flood proofing
Building designed to allow flood water to enter and exit to minimize structural damage, uses flood make-resistant materials and elevates utilities and equipment.
Is wet floodproffing allowed in lieu of elevating the lowest floor above the BFE?
No, not allowed for new residential or dry floodproofing for non-residential. It is allowed for accessory structures, or voluntary retrofits of pre-FIRM buildings provided that the substantial improvements/ damage rule is not triggered
When should flood damage resistant materials be used for property repairs located outside of the SFHA.
If NFIP cliam paid for location outside SFHA use for repairs and renovations.
Why do NFIP regulations require openings in foundations and walls of enclosures Below the BFE
In the event of flood, the openings will allow the flood waters to enter and exit quickly without sustaining damage to the structure, they hydrostatic forces of the water are equalized in and out of the structure.
In addition to openings in the foundation what else is required under the BFE for residential buildings A zones
lowest floor must be elevated to or above the BFE and use of flood damage-resistant material
What is the additional requirement for residential buildings in V zones
lowest floor elevated to or above the BFE, use of flood damage-resistant materials and break away walls only must be non-supporting. No other openings required
Do requirements for enclosures for new construction and substantial improvements residential and non-residential buildings differ?
Requirements for openings is the same for non-residential and residential. Non-residential has option to floodproof to or above the BFE rather than elevate.
What are the basic NFIP requirements for openings in fully enclosed areas below the BFE
Must be no fewer than 2, Net area of openings is equal to 1 SQ inch of opening per 1 SF of the enclosures. Must be Below the BFE and 1 foot above adjacent grade directly under the opening (if interior grade is higher, use this)
How can permit official be certain this minimum criteria is being met.
Calculations for enclosures must be certified by engineer or architect.
How do the openings affect flood insurance rates
If opening doesn’t meet minimum criteria, the floor of the crawlspace or floor of the enclosure becomes the “lowest floor” substantial jacking up the price of flood insurance.
What data is needed to document elevations and information about openings, and what is best way to keep this record.
Use an elevation certificate, which has fields related to enclosures including sq footage of the enclosed area, number of openings within 1 foot above grade and total net area of openings.
What might be added in the comments section of the elevation certificate to clarify compliance with NFIP
special circumstances that without close inspection may lead to conclusion that permit is non-compliant, such as filled stem wall foundation, interior grade is higher than exterior grade, other aspects of non-engineered solutions.
What is specifically allowed use in enclosed areas below the BFE
parking vehicles, building access, storage of low-value items.
How does an enclosed craw/space differ than an typical enclosed area.
No higher than 4 feet from floor to top of joists, provides access to underfloor utilities, pipes, ductwork, conduits, etc.
What items are specifically PROHIBITED in enclosures below the BFE
appliances, heating and cooling, plumping fixtures, and electriial service require more than the minimum to address life safety and electrical code requirements.
Are openings required in non-load bearing perimeter walls
yes, both load bearing and non-load bearing walls are required to have openings.
List several examples of enclosures that require openings
solid perimeter foundation walls- 3 types
crawlspaces or underfloor spaces
below grade crawlspaces
full height underfloor spaces
on which a manufactured home is installed
garage attached to elevated building
enclosed areas under elevated building
enclosed area with breakaway walls
accessory structure- detached garage or shed
Do doors and windows count as allowable openings
No, unless they have opening installed in them, or otherwise meet performance requirement to allow automatic entry and exit of floodwater
What is the required height of openings above grade
openings must be located no higher than 1 foot above the higher of the final interior or exterior grade under the opening,
Can ventilation openings be used to satisfy the NFIP requirement?
In most cases, they are to high, they are installed near top of foundation wall to faciliate air flow.
What is allowable dimensions of a below grade crawlspace that can be below the BFE
4 feet max from below the floor joist to footing, and no more than 2 feet below grade. Flood openings are required.
When is a belowgrade crawlspace considered a basement
if grade inside is below the exterior grade on all sides it is considered a basement under NFIP and higher flood insurance rates will apply. The crawlspace floor elevation will be considered the “lowest floor”
What are additional requirements for a solid permeter foundation wall with full height under floor space
The openings and use restrictions apply here, must meet all NFIP requirements, non-conversion certificate, no appliances, heating and cooling, plumbing and only minimal electric to meet code. Storage, access and vehicle use is all that is allowed. Flood damage resistent materials must be used below BFE.
Is it OK to have attached garage with floor below the BFE
Yes, all requirements apply for use restrictions and openings may be installed in the garage doors.
What happens if garage is built below BFE and it doesn’t have compliant openings?
The garage floor becomes the lowest floor.
Why can’t a garage door itself meet the opening requirment?
It requires human intervention to open it, must be consistent with automatic entry and exit of floodwaters.
what are opening requirement for enclosed area under a building elevated on open foundation in an A zone?
All requirements for enclosed area apply, openings, use restrictions, elevated utilities and flood-damage resistant materials.
Whene are open foundations in riverine areas recommended
If the flow velocities exceed 5 CFS this is significant danger for hydrostatic load and debris impact and scour.
Where can you get the anticipated velocity to know if foundation should be open.
Floodway Data table or complete an H&H analysis iis there is no floodway data.
What are the special circumstances for enclosed areas in coastal A zones or V zones
Open foundations must have breakaway walls, flood openings are required in breakaway walls.
What are the requirements for solid perimeter foundation walls for manufactured homes.
even if the outer perimeter wall is not load bearing it must have openings. otherwise hydrostatic loading could damage piers, anchoring and support system.
what is height of waves in coastal A zone.
1.5 to 3 feet
why do accessory structures need openings?
Detached garage and stoage do not need to be elevated if the openings comply with all requirements for enclosures. Use restrictions apply, buildings must be anchored to prevent floation, collapse or lateral movement when it floods.
If opening is above the BFE does it qualify
only the portion of the openings that is below the BFE counts towards the required net opening.
When might it be advisable to locate an opening less than one foot above grade.
In shallow flood areas the depth of flooding may only be a few inches. you can address problem by elevating the first floor of the enclosure above the bfe SO NO openings needed, or place the encloser very close to or at grade.
what is the difference between non-engineered openings and engineered openings.
non-engineered meet prescriptive requirements of 1 sq in of net open area per 1 sq ft of enclosed area- net open is “permanently open area” . Engineered openings must have engineer certificate to demonstrate that it is consistent with requirements for enclosures
Which of the following is an example of an allowable non-engineered opening:
Air vent, disabled in permanantly open position
Build wall by omitting concrete masonry block in call
Turn concrete masonry block on its side to create opening
Garage Door
All but the garage door, unless it has openings installed in the door itself that meet the standards to be permanently open, and no more than 1 foot above grade.
why should screens or grates be added
to prevent rodents and insects. They do not count against the net open area.
Why is documentation of engineered openings required.
To certify compliance for flood insurance and permit compliance. Evaluation report for ICC-ES, or engineers certificate must be submitted if non-standard technique is used for opening design.
what is the required design requirements for engineered openings for flood insurance.
difference between exterior and interior water levels shall not exceed 1 foot
Automatic exit and entry of water
Minimum rise and fall of water will be 5 feet per hour
equations used to calculate the net opening area has safety factor of 5 to account for debris
Are non-residential buildings allowed to have the first floor flood proofed below the BFE versus elevated in all zones? (construction and substantial improvements)
This rule applies to zone A only, In a Coastal High Hazard Area (Zone V) the lowest floor elevation below the BFE is not allowed regardless of floodproofing type.
How does NFIP describe flood proofing
Making a building watertight, substantially impermeable to flood waters, It is a combination of adjustments or additions to buildings that eliminate or reduce flood damage.
What should be considered before deciding if dryfloodproofing is a good option for non-residential structure.
flood warning time use of the building escape routes flood velocity, depth and frequency debris impact
What form is required to certify non-residential floodproofing design.
Floodproofing Certificate for Non-Residential Structures (FEMA Form 81-65)
Does a residential mixed used building also need a certificate if built in the floodplain
Yes, this will also confirm that all residential uses are located above the floodproofing design elevation
List the NFIP requirements for non-residential structure in the A zone
Lowest floor elevated above the BFE, or building and utilities and sewers below the base flood floodproofed as follows:
structure watertight
walls substantially impermeable
resist hydrostatic and hydrodynamic loads
resist effects of buoyancy
What is NFIP requirment if non-residential structure in AO zone,
lowest floor must be elevated above the highest adjacent grade, and at least as high as specified depth number or 2 feet if no or completely floodproofed to that level.
what 2 certificates are required if floodproofing is chosen over elevation to comply with NFIP
Elevation certificate, and flood proof certificate
Why isn’t floodproofing appropriate in areas that flash flood?
No sufficient warning time
What other elements impact decision to floodproff relative to warning time
must be sufficient warning time to evacuate building an d successfully place floodproofing components or operate pumps and valves
Why is safe access a critical factor in determining wherther or not to floodproof?
If floodplain is area with high hazard (deep water and high velocities) this is a hazard for people trying to access or leave the site. Poor choice for floodproofing.
What is required for evaluation routs adjacent to a floodproofed builidng for safety purposes.
Evacuation route must remain passable long enough for flood components to be installed and personnel to evaluate the site.
