Steel Deck Fastening Systems
Steel Deck Fastener Design and Selection 1.1
1.1.2.4 Fastener Inspection ( Post-Fastener Installation )
Steel deck construction projects may present a challenge with respect to the quality control of connections between sheet steel and the supporting steel structure . Quality control for traditional fastening methods may present a challenge as they typically consist of visual checks and dimensional or size verifications , which may or may not confirm a proper fastening . Field verification of the adequacy of powderactuated mechanical steel deck fastenings can be conducted as described in this section .
The use of mechanical fasteners does not imply a need to inspect every fastening point unless specified by the Structural Engineer . No guideline standards are published by SDI , AWS , AISC or OSHA for percentages of steel deck connections that must be checked or that can be unsatisfactory . This determination must be made by the Structural Engineer and Authority Having Jurisdiction .
Figure 9 : Hilti Power Adjustment Guide
Hilti has multiple services and aids in place that help ensure steel deck fastenings are done correctly the first time . Together with a commitment to field quality control by the steel deck installer , these systems may alleviate the need for postfastener installation inspection . Hilti has over one thousand Account Managers and Field Engineers available for training steel deck installers . This handson training includes the use of the Hilti Powder-Actuated Tools in accordance with ANSI A10.3 safety requirements , use of the Deck Fastener Selector Gauge , proper steel deck layout and end / corner lap nesting as discussed in Section 1.1.2.3 . Proper powder-actuated fastener , tool and cartridge selection as discussed in Section 1.1.3 , as well as the use of the Hilti Power Adjustment Guide , shown in Figure 9 and discussed in more detail in Section 1.1.3.3 , are also key elements of the installer training . Furthermore , the Hilti DX 860-HSN tools come equipped with piston brakes , which virtually eliminate the possibility of overdriven fasteners .
There are three main characteristics of proper fastenings that must be considered :
1 . Fasteners installed in proper locations . The fasteners must be installed in the proper steel deck valleys or flutes in accordance with the structural roof and floor deck plans and design , and in the proper location in the base steel ( Reference
Section 1.1.2.3 ). The fastener point must penetrate into , but not necessarily through , the supporting steel ( top chord or flange ), depending on the fastener / deck / base steel configuration .
2 . Clamping of fastened part to base material . The fasteners must clamp the steel deck down to the base steel ( top chord or flange ). There should not be any visible gaps between the steel deck and the base steel or between steel deck laps .
3 . Washer placement and condition . In general , the fastener washer edges must be clamping the steel deck sheet to the base steel . The washers should not curl upwards away from the deck surface and must not be digging or cutting into the steel deck surface . For the X-HSN 24 fastener , the top hat washer must be compressed . For the X-ENP-19 fastener , the piston mark ( indentation ) should be clearly visible on the fastener washer as shown in Figure 10 .
Piston Mark
Figure 10 : X-ENP-19 L15 Piston Mark ( indentation )
When the inspector is unclear about the compression of the top hat washer or the piston mark , the Hilti Power Adjustment Guide may be used to measure for optimal powder-actuated fastener nailhead stand-off , h NVS
. Note that measuring nail head stand-off does not verify proper fastener embedment unless the steel deck and base material are tightly clamped , with the base steel not deformed or bent . Conversely , measuring nail head stand-off does not confirm an improper fastening . If slightly outside the range , further investigation into the three characteristics of proper fastenings given above should be completed .
The following Figures 11 and 12 provide visual examples of proper and improper steel deck fastenings for Hilti powder-actuated bar joist ( X-HSN 24 ) and structural steel ( X-ENP-19 L15 ) fasteners , respectively .
Inspection of the installed steel deck and installation of roof coverings , insulation and membrane should be done soon after steel deck installation to assist in alleviating corrosion or other issues that could arise due to long-term exposure . Fasteners must be completely protected from the weather within 180 days after installation .
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