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]

The Cost Of Water Damage

How Can I Save Money? The price you pay for your homeowners insurance can vary by hundreds of dollars, depending on the size of your house and the insurance company you buy your policy from. Here are some ways to save money:1. Shop around Prices vary from company to company, Water Damage The Cost Of Water Damage so it pay  read more..

How To Dehumidify Your Water Damaged Home

Figure 2 shows a picture of the experimental system. The evaporator and condenser chambers are Dehumidification How To Dehumidify Your Water Damaged Home shown in the center of the picture. Both are wrapped with black polyethylene foam insulation to prevent heat transfer to or from the ambient environment. The air and water piping is also cov  read more..

Should You Remove Insulation In An Attic After Rac

Under this alternative ADC would not assist in resolving bird damage problems. Current and potential cooperating facilities would have to withstand losses and the risk of disease problems or resort to their own BDM. Their costs for conducting their own BDM would depend on the methods chosen.   read more..

How To Stop A Basement Water Leak Waterproofing

The hydrologic cycle is the continuous circulation of water from land and sea to the atmosphere and back again : water evaporates from oceans, lakes, and rivers into the atmosphere. This water later precipitates as rain or snow onto the land where it evaporates or runs off into streams and rive  read more..

How To Catch Birds In The Home In Arizona

The problem of starling damage to livestock feed has been documented in France and Great Britain, and in the United States. As the science of raising cattle for slaughter progressed from range to feedlot operations, the starling Animal Damage How To Catch Birds In The Home In Arizona problem intensified. 

The concent  read more..

Crime Scene Photos

This report describes states' laws that directly address the disclosure of crime scene photographs, autopsy reports, and 911 tapes and transcripts. We conducted a 50-state survey and found (1) nine states that have laws directly addressing the disclosure of Crime Scene Cleanup Crime Scene Photos scene photos, (2) 26 states with laws  read more..

Lead Paint Removal Poisoning

Where the employer does establish that the employee is exposed to levels of lead below 2,500 µg/m3, the employer may provide the exposed employee with the appropriate respirator prescribed for use at such lower exposures, in accordance with Table I of this section. Interim protection as described i  read more..

Tenant Move Out

Smoke damage, Tenant Move out


A new report proposes that United States landlords pay about $1000 extra for each tenant who smokes compared to the cost to rent to a person who has never smoked cigarettes. Experts say the report is the first to  read more..

Wind Damage And Emergency Board Up

Plywood shutters that you create yourself, if placed correctly, could provide a high degree of Odor Control Wind Damage And Emergency Board Up coverage from flying debris during a storm. Plywood shutters could be placed on all kinds of houses. Measure every window and every door that has glass, and add 8 inches to all the height and w  read more..

Fire Damage Electronic Restoration Classes

Some Micro-miniature and Nano-miniature type connectors have the option of pre-terminated cross linked ETFE (TefzelTM) insulated wire pigtails. Users are advised that some ETFE insulations are known to out-gas trace amounts of corrosive fluorine over time. When this wire is used with nickel coated m  read more..