PolyPDF vs HVAC Duct Calculator

The PDF app built for AEC professionals who demand precision. PolyPDF revolutionizes how architects, engineers, and construction professionals work with PDF drawings and documents. Our advanced line detection algorithms and measurement tools turn static PDFs into intelligent, workable documents. KEY FEATURES Smart Line Detection - Advanced algorithms automatically detect lines in technical drawings - Three detection modes: Corner, Hough, and Simple for different document types - Perfect for CAD exports, scanned blueprints, and technical diagrams Precision Measurement Tools - Measure distances, areas, and angles directly on PDFs - Set custom scales for accurate real-world measurements - Export measurement data for estimates and reports Professional Markup - Comprehensive annotation toolkit designed for technical review - Callout bubbles with customizable arrow styles - Highlight, underline, and strikethrough text - Add shapes, lines, and freehand drawings - Color-coded annotations for different disciplines Built for Productivity - Native iPad and iPhone support with seamless sync - Document browser with visual previews - Page thumbnails for quick navigation - Annotation sidebar for easy management - Multi-tab support for working with multiple documents Why AEC Professionals Choose PolyPDF - Designed specifically for construction and design workflows - No more printing drawings for markup - Reduce errors with digital precision tools - Streamline communication with clear, professional annotations - Save time on site visits and punch lists PREMIUM FEATURES (Coming Soon) - Cloud sync across all devices - Team collaboration tools - Custom annotation libraries - Advanced measurement reports - CAD layer support - Batch processing Join thousands of AEC professionals who've upgraded their PDF workflow. Download PolyPDF today and experience the difference precision makes.

HVAC Duct Calculator is a practical engineering calculation tool for quick ventilation and duct sizing checks. Use it during design reviews, field checks, early estimates, and technical training when you need fast preliminary calculations for HVAC ductwork and air terminals. Key calculations: - Duct calculation Calculate air velocity, friction loss, and equivalent round duct diameter from airflow and duct dimensions. - Duct shapes Run preliminary checks for rectangular, round, and oval duct options. - Airflow and air change calculation Estimate required airflow from room dimensions and air change values, with results in m3/h and L/s. - Grille, louver, and diffuser checks Check face velocity using airflow, dimensions, and free area/effective area ratio. - Unit systems Work with Metric SI or US inch units. - Sharing Share calculation results through the native iOS share sheet. Who it is for: - Mechanical engineers - HVAC design teams - Site and commissioning teams - Technicians - Ventilation and air-conditioning professionals - Students who need preliminary technical checks The app does not include ads, account signup, or subscriptions. Core calculation tools are free. An optional one-time VIP unlock can enable advanced local workflow tools such as duct takeoff, quick sizing, saved records, and professional helper screens. Important note: This app is designed for information and preliminary calculation only. Results are not a substitute for final engineering design, manufacturing, installation, code compliance, or professional judgment. Always verify results with applicable standards, manufacturer data, project specifications, and a qualified engineer. For feedback, suggestions, or bug reports, use the support options inside the app.