CRSI Rebar Reference vs Duct Construction
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CRSI Rebar Reference
Access essential data for reinforcing bars (rebar) including specifications, hook details, and marking requirements. This app serves as a quick reference for industry standards and links to online resources.
- ASTM standard reinforcing bar specifications
- Standard hook details (90, 135, 180 degrees)
- Stirrup/tie hook details
- ASTM reinforcing bar marking requirements
- Minimum yield and tensile requirements
- Links to CRSI online resources
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QUICK REFERENCE! This ready reference app from the Concrete Reinforcing Steel Institute is a handy desk and field resource and includes information on ASTM standard reinforcing bars (rebar), standard hook details, standard stirrup/tie hook details, and ASTM reinforcing bar marking requirements. The app provides standard rebar specifications including sizes, diameters, areas and weights along with 90-, 135- and 180-degree hook details. Minimum yield and minimum tensile requirements per ASTM are also included. Industry standard bar markings for inch-pound rebar is illustrated for grades 40, 50, 60, 75, 80, 100 (A615), 100 (A1035), and 120. Links to the CRSI’s online resources are included.
Duct Construction
This app helps determine duct construction and reinforcement options based on duct size and system pressure class. It provides condensed lists of suitable options, saving time spent on manual calculations and table lookups. Results are based on industry standards for galvanized steel duct sheets.
- Duct size range from 2" to 120"
- Pressure classes up to 4 in.wg
- Calculates duct weights per linear foot
- Determines required duct gauge and reinforcement spacing
- Clear illustrations for reinforcement types
- Simple and effective UI design
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Get all duct construction and reinforcement options by entering the duct size and system pressure class. The aim of the app is to save time spent browsing through tables and texts to determine suitable options, by relying on the most widely used standards and providing a condensed list of available duct construction options. The results are based on galvanized steel duct sheets conforming to ASTM A653 & A924. The app does not cover all aspects of duct construction, as it is intended as a guide; Reliance on related standards, as well as good engineering sense is the basis for proper design. Features: 1. Duct sizes from 2" to 120" 2. Pressure classes 0.5 in.wg, 1 in.wg, 2 in.wg, 3 in.wg and 4 in.wg. 3. Provides the duct weights for each option per linear foot. 4. Provides required duct gauge and reinforcement spacing. 5. Clear illustration for each reinforcement type, as well as dimensions. 6. Simple and effective UI design. Roadmap / Upcoming updates: 1. SI units. 2. More pressure class options. 3. User will be able to save and retreive duct data for future reference. 3. More Reinforcement options, including tie-rodding. Request a feature: welmurr@icloud.com
Screenshots
Verdict
The clearest difference is price: CRSI Rebar Reference at Free against Duct Construction's $0.99. CRSI Rebar Reference also leads on rating (3.3 vs 1.0) and review sentiment (33% vs 0%). Duct Construction's advantage is in-app purchases (none vs 3) and chart position (#194 vs unranked). On ads 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
CRSI Rebar Reference is free to download; Duct Construction costs $0.99 up front. CRSI Rebar Reference sells 3 one-off in-app purchases. Duct Construction asks for nothing beyond the download.
CRSI Rebar Reference holds the better App Store score, 3.3 against 1.0. That said, the two scores are not equally well evidenced: CRSI Rebar Reference has 16 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 33% of CRSI Rebar Reference's written reviews are positive against 0% of Duct Construction's.
CRSI Rebar Reference ships an update every 5 weeks, Duct Construction every 10 months. The most recent releases landed on June 1, 2026 and September 9, 2026 respectively.
| Parameter | CRSI Rebar Reference | Duct Construction |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | 3.3 (16 ratings) — better | 1.0 (1 ratings) |
| Positive reviews | 33.3% of reviews — better | 0.0% of reviews |
| Number of ratings | 16 — better | 1 |
| Update frequency | Every 5 weeks — better | Every 10 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free — better | Paid |
| Best chart rank | — | #194 — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.1 — better | 17.6 |
| Further details — not scored | ||
| Size | 51 MB | 1 MB |
| Age rating | 17+ | 4+ |
| Developer | Concrete Reinforcing Steel Institute | Wassim Murr |
Customer experience
CRSI Rebar Reference
Duct Construction
In-app purchases
CRSI Rebar Reference
- CRSI - Rebar Identifier Module$2.99
- CRSI Development Length ACI$4.99
- CRSI Development length AASHTO$4.99
Duct Construction
No in-app purchases
Questions
Is CRSI Rebar Reference free?
Is Duct Construction free?
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Which is updated more often, CRSI Rebar Reference or Duct Construction?
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