Span Calc vs Richardson Alerting
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Span Calc
Calculate maximum horizontal spans for wood joists and rafters using various lumber species and grades. Compares multiple options for common loading conditions based on NDS® standards.
- Calculates joist and rafter spans
- Supports all softwood and hardwood lumber
- Uses 2021 NDS® for Wood Construction
- Compares multiple species and grades
- Handles common loading conditions
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The American Wood Council (AWC) Span Calculator for Wood Joists and Rafters (Span Calc) performs calculations for all species and grades of commercially available softwood and hardwood lumber as found in the 2021 National Design Specification® (NDS®) for Wood Construction. Joists and rafter spans for common loading conditions can be determined. A span options calculator allows selection of multiple species and grades for comparison purposes. Supported by the Softwood Lumber Board. Maximum horizontal spans for joists and rafters are calculated based on the following assumptions and conditions: · Joists and rafters are oriented to support vertical loads applied to the narrow (1.5 in. thick) face of the member, resulting in strong-axis bending. · At least three joists or rafters are installed parallel to one another and spaced not more than 24 inches on-center, with properly designed sheathing attached on the top (compression) edge of each joist or rafter. · Joists and rafters are single-span with adequate structural support at each end. The Span Calculator does not address cantilevered joists and rafters, multiple-span joists and rafters, or spliced joists and rafters. · For joists and rafters, most building codes specify a minimum bearing length of 1.5 inches on wood or metal and not less than 3 inches on masonry or concrete. These minimum bearing lengths are to be used in the absence of calculated bearing lengths. Consult the local building code for specific requirements. · Joists and rafters carry only combinations of dead load plus live load (D + L), dead load plus snow load (D + S), or dead load plus roof live load (D + Lr). The Span Calculator does not address wind load or seismic load. · Buildings in regions with ground snow loads greater than 70 psf should not use the prescriptive provisions of the governing building code without approval of the authority having jurisdiction. Buildings in these high snow zones should be designed in accordance with accepted engineering practice. While every effort has been made to insure the accuracy of the information presented, and special effort has been made to assure that the information reflects the state-of-the-art, neither the American Wood Council nor its members assume any responsibility for any particular design prepared from this Span Calculator application. Those using this Span Calculator assume all liability from its use.
Richardson Alerting
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Mach Alert is a full featured fire station alerting (FSA) solution designed to provide state of the art alerting functionality and reliability to public safety answering points (PSAP), fire and EMS facilities, and, with optional add-ons, to first responders in the field. Whether operating as a standalone system or via interface to a computer aided dispatch (CAD) product, Mach Alert is designed to minimize time spent dispatching at the 911 center and maximize the amount of critical information delivered to first responders when they need it most with tones, voice, and a robust catalog of add-ons and customization options.
Screenshots
Verdict
The clearest difference is update cadence: Span Calc at every 10 days against Richardson Alerting's every 2 months. Richardson Alerting's advantage is iOS requirement (12.0 vs 14.2). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Span Calc ships an update every 10 days, Richardson Alerting every 2 months. The most recent releases landed on October 12, 2026 and October 2, 2026 respectively.
| Parameter | Span Calc | Richardson Alerting |
|---|---|---|
| Price | Free | Free |
| Rating | 2.9 (15 ratings) — better | — |
| Positive reviews | 29.6% of reviews | — |
| Number of ratings | 15 — better | — |
| Update frequency | Every 10 days — better | Every 2 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 14.2 | 12.0 — better |
| Further details — not scored | ||
| Size | 168 MB | 68 MB |
| Age rating | 17+ | 4+ |
| Developer | American Wood Council | Mach Alert Inc. |
In-app purchases
Span Calc
No in-app purchases
Richardson Alerting
No in-app purchases
Questions
Is Span Calc free?
Is Richardson Alerting free?
Do Span Calc or Richardson Alerting have ads?
Which is updated more often, Span Calc or Richardson Alerting?
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