How do I get SDS from the ASCE Hazard Tool?

Enter the project address and risk category on this page to auto-fill SDS from the public ASCE hazard data source. You can still open ascehazardtool.org to cross-check the mapped location and hazard result when needed.

What is SDS in ASCE 7-22 seismic design?

SDS is the design spectral response acceleration parameter at short periods. It is one of the main seismic inputs used to determine component force demands for anchorage, bracing, and nonstructural seismic design under ASCE 7-22.

When does the component importance factor Ip become 1.5?

Under ASCE 7-22 Section 13.1.3, Ip becomes 1.5 when the component is required for life-safety, contains hazardous materials above threshold, or must remain functional in a Risk Category IV facility.

What happens if Ip is 1.5 instead of 1.0?

A component importance factor of 1.5 increases the seismic design force compared with Ip = 1.0. In practice, that can increase anchor demand, brace demand, and the likelihood that a listed OPM or OSP certification no longer covers the project conditions.

What does z/h represent in seismic anchorage design?

z/h is the ratio of component installation elevation z to total building structural height h. It is a key input for height amplification and upper-floor seismic demand in ASCE 7-22 Chapter 13.

What z/h value should I use for equipment at or below grade?

For equipment installed at grade or below grade, this planning tool treats z/h as 0. That aligns with the common early-design interpretation that no height amplification applies when the component elevation is effectively at the base reference level.

Can z be greater than h in the calculator?

No. Equipment elevation z should not exceed the total building structural height h. If z is greater than h, the input set should be reviewed because the resulting z/h ratio would not represent a valid ASCE 7-22 building-height condition.

Does this tool replace a stamped seismic anchor calculation?

No. This calculator is an intake and coordination tool for SDS, Ip, z/h, and table lookups. Final anchorage design still requires project-specific engineering, code review, and anchor checks under the governing ASCE 7-22 and ACI requirements.

ASCE 7-22 seismic anchor calculator

ASCE 7-22 SDS, I_p & z/h Calculator

Use this seismic anchor calculator to organize the ASCE 7-22 input chain in one place: project address for SDS lookup, component importance factor I_p, installation ratio z/h, and common Chapter 13 C_Ar, R_po, and Ω₀ selections for equipment anchorage and nonstructural seismic design.

Open ASCE Hazard Tool Read the Chapter 13 guide

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Project input workspace

Use this as a fast pre-design worksheet before running the full anchor calculation.

Project address

Enter the jobsite address, then fetch SDS automatically using the public ASCE 7-22 hazard data for the selected risk category.

SDS from ASCE hazard data

Auto-fetch uses the public ASCE risk-category seismic layer based on the resolved address point.

Building category

Use the ASCE 7-22 risk category for the building so the I_p check aligns with the standard.

Building height reference

Below or at gradeUse grade level or below-grade installation where z/h should be treated as 0.Above gradeUse the building structural height h when the component is installed above grade.

Building structural height h (ft)Equipment elevation z (ft)

Importance factor Ip checks

Life-safety functionUse when the component is required for life-safety performance after the earthquake.Hazardous substance containmentUse when the component contains or restrains hazardous substances that must remain contained.Essential facility operation requiredUse when the component must remain functional to support essential facility operation after the event.Designated seismic systemUse when the component is classified as a designated seismic system for the project.Active equipmentUse when the component is active equipment that must operate as part of the post-earthquake function.

ASCE 7-22 table

Component type

Exact Table 13.6-1 row from the uploaded Chapter 13 extract.

Live results

Planning-level outputs for early seismic input coordination.

SDS

Fetch SDS

Component importance factor Ip

Ip basis

Ip = 1.0 based on the current ASCE 7-22 selections.

Selected ASCE table

Table 13.6-1 — mechanical & electrical components

Selected component

Wet-side HVACR, boilers, furnaces, atmospheric tanks and bins, chillers, water heaters, heat exchangers, evaporators, air separators, manufacturing or process equipment, and other mechanical components constructed of high-deformability materials

z/h ratio

Enter h and z

CAr

Using above-grade CAr from the selected table row.

Rpo

1.5

Ω0

Next step

Move from preliminary inputs to a full PE/SE-reviewed seismic calculation.

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Add the project address above so estimators, PMs, and engineers stay aligned during SDS lookup.

Table 13.6-1 — mechanical & electrical components

Full quick-reference listing for the currently selected ASCE 7-22 Chapter 13 table.

40 listed rows

1.Air-side HVACR, fans, air handlers, air conditioning units, cabinet heaters, air distribution boxes, and other mechanical components constructed of sheet metal framing

2.Wet-side HVACR, boilers, furnaces, atmospheric tanks and bins, chillers, water heaters, heat exchangers, evaporators, air separators, manufacturing or process equipment, and other mechanical components constructed of high-deformability materials

3.Air coolers (fin fans), air-cooled heat exchangers, condensing units, dry coolers, remote radiators, and other mechanical components elevated on integral structural steel or sheet metal supports

4.Engines, turbines, pumps, compressors, and pressure vessels not supported on skirts and not within the scope of Chapter 15

5.Skirt-supported pressure vessels not within the scope of Chapter 15

6.Elevator and escalator components

7.Generators, batteries, inverters, motors, transformers, and other electrical components constructed of high-deformability materials

8.Motor control centers, panel boards, switch gear, instrumentation cabinets, and other components constructed of sheet metal framing

9.Communication equipment, computers, instrumentation, and controls

10.Roof-mounted stacks, cooling and electrical towers laterally braced below their center of mass

11.Roof-mounted stacks, cooling and electrical towers laterally braced above their center of mass

12.Lighting fixtures

13.Other mechanical or electrical components

14.Manufacturing or process conveyors (nonpersonnel)

15.Vibration-isolated components and systems — components and systems isolated using neoprene elements and neoprene isolated floors with built-in or separate elastomeric snubbing devices or resilient perimeter stops

16.Vibration-isolated components and systems — spring-isolated components and systems and vibration-isolated floors closely restrained using built-in or separate elastomeric snubbing devices or resilient perimeter stops

17.Vibration-isolated components and systems — internally isolated components and systems

18.Vibration-isolated components and systems — suspended vibration-isolated equipment, including in-line duct devices and suspended internally isolated components

19.Equipment support structures and platforms — support structures and platforms where Tp/Ta < 0.2, or Tp ≤ 0.06 s, per Section 13.6.4.6

20.Equipment support structures and platforms — seismic force-resisting systems with R > 3

21.Equipment support structures and platforms — seismic force-resisting systems with R ≤ 3

22.Equipment support structures and platforms — other systems

23.Distribution system supports — tension-only and cable bracing

24.Distribution system supports — cold-formed steel rigid bracing

25.Distribution system supports — hot-rolled steel bracing

26.Distribution system supports — other rigid bracing

27.Distribution system supports — lateral resistance provided by rods in flexure

28.Distribution system supports — vertical cantilever supports such as pipe tees and moment frames above and supported by a floor or roof

29.Distribution systems — piping in accordance with ASME B31 (2001, 2002, 2008, 2010), including in-line components with joints made by welding or brazing

30.Distribution systems — piping in accordance with ASME B31, including in-line components, constructed of high- or limited-deformability materials, with joints made by threading, bonding, compression couplings, or grooved couplings

31.Distribution systems — piping and tubing not in accordance with ASME B31, including in-line components, constructed of high-deformability materials, with joints made by welding or brazing

32.Distribution systems — piping and tubing not in accordance with ASME B31, including in-line components, constructed of high- or limited-deformability materials, with joints made by threading, bonding, compression couplings, or grooved couplings

33.Distribution systems — piping and tubing constructed of low-deformability materials, such as cast iron, glass, and nonductile plastics

34.Distribution systems — duct systems, including in-line components, constructed of high-deformability materials, with joints made by welding or brazing

35.Distribution systems — duct systems, including in-line components, constructed of high- or limited-deformability materials, with joints made by means other than welding or brazing

36.Distribution systems — duct systems, including in-line components, constructed of low-deformability materials, such as cast iron, glass, and nonductile plastics

37.Distribution systems — electrical conduit, cable trays, and raceways

38.Distribution systems — bus ducts

39.Distribution systems — plumbing

40.Distribution systems — pneumatic tube transport systems

Why this seismic anchor calculator matters

Many project teams lose time before the actual seismic anchor calculation even starts. The bottleneck is usually upstream: confirming S_DS, deciding whether I_p = 1.0 or 1.5, calculating the equipment elevation ratio z/h, and pulling the correct C_AR, R_po, and Ω₀ values from ASCE 7-22. This page turns those scattered steps into one clean engineering workflow.

Important note

This is a planning and intake tool, not a substitute for a project-specific design. It should be used together with the HCAI OSP and OPM databases to check whether an existing seismic certification appears capable of meeting the site seismic demand. Final acceptance still requires project-specific engineering review, certification scope verification, and the governing ASCE 7-22 and ACI 318 checks.

ASCE 7-22 SDS, Ip & z/h Calculator