Wind Damage >> Hurricane Protection Techniques

 For other basic wind speeds, or for an importance factor of 1, multiply the tabulated number of #12 screws by to determine the required number of #12 screws or (¼ pan-head screws) required for the desired basic wind speed, VD (mph) and Hurricane Protection Techniques importance factor, I.4. 

For other roof heights up to 200', multiply the tabulated number of #12 screws by (1.00 + 0.003 [h - 30]) to determine Hurricane Protection Techniques the required number of #12 screws or ¼ pan-head screws for buildings between 30' and 200'.

Example A: 24" x 24" exhaust fan screwed to curb (table row 7), Base Case conditions (see Note 1): 2.5 screws per side; therefore, Hurricane Protection Techniques round up and specify 3 screws per side.Example B: 24" x 24" exhaust fan screwed to curb (table row 7).

Base Case conditions, except 120 mph and importance factor of 1: 1202 x 1 902 x 1.15 = 1.55 x 2.5 screws per side = 3.86 screws per side; Hurricane Protection Techniques therefore, round up and specify 4 screws per side.Example C: 24" x 24" exhaust fan screwed to curb (table row 7).

Base Case conditions, except 150' roof height: 1.00 + 0.003 (150' - 30') = 1.00 + 0.36 = 1.36 x 2.5 screws per side = 3.4 screws per side; therefore, Hurricane Protection Techniques round down and specify 3 screws per side.* This factor only applies to the long sides. At the short sides, use the fastener spacing used at the long sides. 

Fan Cowling Attachment: Fans are frequently blown off their curbs because they are poorly attached. When fans are well attached, Hurricane Protection Techniques the cowlings frequently blow off (see Figure 3). Unless the fan manufacturer specifically engineered the cowling attachment to resist the design wind load, cable tie-downs (see Figure 4) are recommended to avoid cowling blow-off. 

For fan cowlings less than 4 feet in diameter, 1/8-inch diameter stainless steel cables are recommended. Figure 3 caption. Cowlings blew off two of the three fans shown in this photo. Cowlings can tear roof membranes and break glazing. [end of caption] Figure 4 caption. To overcome blow-off of the fan cowling, Hurricane Protection Techniques this cowling was attached to the curb with cables.  

For larger cowlings, use 3/16-inch diameter cables. When the basic wind speed is 120 mph or less, specify two cables. Where the basic wind speed is greater than 120 mph, Hurricane Protection Techniques specify four cables. To minimize leakage potential at the anchor point, it is recommended that the cables be adequately anchored to the equipment curb (rather than anchored to the roof deck). 

The attachment of the curb itself also needs to be designed and specified. Ductwork: To avoid wind and windborne debris damage to rooftop ductwork, Hurricane Protection Techniques it is recommended that ductwork not be installed on the roof (see Figure 5). If ductwork is installed on the roof, it is recommended that the gauge of the ducts and their attachment be sufficient to resist the design wind loads. 

Figure 5 caption. Two large openings remained (circled area and inset to the right) after the ductwork on this Hurricane Protection Techniques roof blew away. [end of caption] Condensers: In lieu of placing rooftop-mounted condensers on wood sleepers resting on the roof (see Figure 6), it is recommended that condensers be anchored to equipment stands. 

(Note: the attachment of the stand to the roof deck also needs to be designed to resist the design loads.) In addition to anchoring the base of the condenser to the stand, Hurricane Protection Techniques two metal straps with two side-by-side #14 screws or bolts at each strap end are recommended (see Figure 7). Figure 6 caption. Sleeper-mounted condensers displaced by high winds.  

Figure 7 caption. This condenser had supplemental securement straps (see arrows). Two side-by-side screws with the proper edge and Hurricane Protection Techniques end distances are recommended at the end of the strap. [end of caption] Vibration Isolators: 

When equipment is mounted on vibration isolators, an isolator that has sufficient resistance to meet the design uplift loads should be specified and installed, or Hurricane Protection Techniques an alternative means to accommodate uplift resistance should be provided (see Figure 8). Figure 8 caption. 

The equipment on this stand was resting on vibration isolators that provided lateral resistance Hurricane Protection Techniques but no uplift resistance (above). A damaged vibration isolator is shown in the inset (left). [end of caption] Access Panel Attachment: Access panels frequently blow off. 

To minimize blow-off of access panels, job-site modification will typically be necessary (for example, the attachment of hasps and locking devices such as a carabiner). The modification details will need to be tailored for the equipment, Hurricane Protection Techniques which may necessitate detail design after the equipment has been delivered to the job site. 

Modification details should be approved by the equipment manufacturer. Equipment Screens: Equipment screens around rooftop equipment are frequently blown away (see Figure 9). Equipment screens should be designed to resist the wind loads derived from ASCE 7. Note: The extent that screens may reduce or Hurricane Protection Techniques increase wind loads on equipment is unknown. 

Therefore, Hurricane Protection Techniques the equipment behind screens should be designed to resist the loads previously noted. Figure 9 caption. Several of the equipment screen panels were blown away. Loose panels can break glazing and puncture roof membranes. 

Other resources: Three publications pertaining to seismic restraint of equipment provide general information on fasteners and Hurricane Protection Techniques edge distances: • Installing Seismic Restraints for Mechanical Equipment (FEMA 412) • Installing Seismic Restraints for Electrical Equipment (FEMA 413)• Installing Seismic Restraints for Duct and Pipe (FEMA 414).

Figure 7 caption: A failed prong-type splice connector. If conductors become detached from the roof, they are likely to pull from pronged splice Hurricane Protection Techniques connectors. [end of Figure 7 caption] Figure 8 caption: To avoid free ends of connectors being whipped around by wind, bolted splice connectors are recommended because they provide a more reliable connection.  

Strengthening Attachment of Existing Systems: On critically important buildings that use adhesively-attached connectors and pronged splice connectors,Hurricane Protection Techniques it is recommended that attachment modifications based on Construction Guidance be made in order to provide more reliable securement. [End of Recovery Advisory]

How To Paint Over Fire Damage On Drywall

The president of NFPA (National Fire Protection Association) today called for all nursing homes in the U.S. to be equipped with fire sprinklers, in the wake of two recent nursing home fires in Hartford and Nashville, Fire Damage How To Paint Over Fire Damage On Drywall where a total of 24 people died. (See NFPA's fact sheet on nursing home fire s  read more..

Get Rid Of Decomposed Animal Odors

Can biosolids be used for mine reclamation? Biosolids have been used successfully at mine sites to establish sustainable vegetation. Not only does the organic matter, inorganic matrix and nutrients present in the biosolids reduce the bioavailability of toxic substances often found in highly disturbe  read more..

Compulsive Animal Hoarding

Compulsive hoarding isn't anything new, as matter of fact, hoarding has existed as long as there were people and there were things to be collected. But until recently, when these television shows started to bring this disease to light and let the world learn more about Hoarding Compulsive Animal Hoarding. Also there are sh  read more..

California Asbestos Tile Removal Requirements

Identifying hazardous materials before starting work on a project site protects worker health and safety, building occupants, and the financial viability of the project. Doing this up front can help you choose the appropriate inspectors, consultants and contractors and avoid costly change orders or  read more..

Fema Debris Disposal And Flood Zones

Household Chemicals (i.e., Household Hazardous Waste (HHW)) can be taken to a county or municipal HHW facility for recycling or potentially reuse. Check with your local environmental health representative to see if a temporary HHW collection site has been established. If HHW cannot safely be removed  read more..

How To Restore Water Damaged Archive Photos

The New Orleans Charter is the product resulting from the two symposia: Museums in Historic Buildings held in Montreal, Quebec (1990) and New Orleans, Louisiana (1991) and Document restoration How To Restore Water Damaged Archive Photos co-sponsored by the American Institute for Conservation of Historic and Artistic Works (AIC) and The Association   read more..

Flood Damage

So your tenants moved out without notice about Tenant Move Out Cleanup Flood Damage. So your tenants of moved out and upon inspecting the premises after they moved, you find water all over the floors. First step is, call a professional water restoration company. Let them deal with your insurance company as they know how to   read more..

How Do I Clean Up After The Finished Basement Floo

Basement and Yard Water Problems
 Each year, the Water Resources Center receives dozens of phone calls and emails from people experiencing problems with unwanted water. Many of the calls start Basement Drying How Do I Clean Up After The Finished Basement Floo with "I think my house is built on a spring”. The symptoms may include w  read more..

Asbestos In Homes

What programs are available to help individuals with asbestos in homes-related diseases? Some people with Asbestos Abatement Asbestos In Homes-related illness may be eligible for Medicare coverage. Information about benefits is available from Medicare’s Regional Offices, located in 10 major cities across the United States and s  read more..

Mold Testing Kit

How Can I Tell If I Have Mold ? The most practical way to find a mold problem is by using your eyes to look for mold growth and by using your nose to locate the source of a suspicious odor.If you see mold or if there is an earthy or musty smell, you  read more..