This video discusses the steps required to design a working iron lung respirator. An iron lung is a negative pressure ventilator (NPV). It is intended for worst case scenarios where all other resources have failed and the alternative is death. Many developing countries do not have the infrastructure, money, resources and technology to acquire or build Positive Pressure Ventilators (PPV). Iron Lungs were invented in the 1930s and can be built using global readily available resources. PDF version: http://www.cadvision.com/blanchas/Roadmap-IronLung.pdf This video validates the design concept: Building an Iron Lung Respirator Part 1 of 2: https://www.youtube.com/watch?v=ESbnjHXrIQ0 Vacuum Testing a Concrete Form Tube: https://www.youtube.com/watch?v=U0MF6cZMLu8 Successful Vacuum tested two 55 gallon steel drums welded/soldered together to 150 cm of h20: Part 1: https://www.youtube.com/watch?v=YRM26dReTlE Part 2: https://www.youtube.com/watch?v=tNn0ZXQZ7t0 Further testing revealed that the loud banging heard is cause by the lid and bottom being "sucked in". Both end pieces would be replaced in an iron lung and the loud banging noise may not be important. The bottom would be replaced with a bellows and the lid replaced with a head piece. This was determined during these videos: Part 1 of 2: Use a Vehicle's Intake Manifold as a Vacuum Source https://www.youtube.com/watch?v=Dq4pndD8-aE part 2 of 2: Use a Vehicle's Intake Manifold as a Vacuum Source https://www.youtube.com/watch?v=a78zm5_E2dU Alternative resources to 55 gallon steel drums: Fiber concrete column forms, or forming tubes (made of a thick cardboard), large air compressor tanks, propane tanks, etc.. *_ Respirator ventilators are not toys and can damage a patient’s lungs or kill the patient if not used properly! ** -- Only qualified medical personnel should be operating them or those under the direction of a qualified medical person.-- Here is an Open source Positive Pressure Ventilator design that does not use electronic control systems: https://www.youtube.com/watch?v=AecHnt-CF5k This is an excellent resource to learn about respirators and lung function: A Guide to Designing Low-cost Respirators: https://www.youtube.com/watch?v=7vLPefHYWpY Other Resources: How to make a Manometer https://www.youtube.com/watch?v=gsI6wOeqRlI 1956 Iron Lung https://www.youtube.com/watch?v=H1WOPsA_gL8 Kansas City polio survivor is one of last iron lung users in U.S (18 cm of water) https://www.youtube.com/watch?v=y6ezbEW9QZ4 The Last Few Polio Survivors https://www.youtube.com/watch?v=gplA6pq9cOs The Iron Lung and Polio https://www.youtube.com/watch?v=cUCqsl6JROg The Iron Lung https://www.youtube.com/watch?v=xUOlLNKBHiY The Both Mechanical Respirator (1939) part 1 of 3 series https://www.youtube.com/watch?v=M_dt3GeCtMo Artificial Respirators (1940s?) Part 1 of 6 Part Series https://www.youtube.com/watch?v=3DzTBN-yrMc 55 Gallon Drum Vacuum Test https://www.youtube.com/watch?v=CONxG2Kb160 How To Make a One-Way Check Valve - For Cheap!! https://www.youtube.com/watch?v=DG6own141z0 Example reed valve operation at the 26 sec mark: https://photos.app.goo.gl/VyoWrnEmdiw89ap46