{"id":997675,"date":"2026-09-08T08:00:00","date_gmt":"2026-09-08T06:00:00","guid":{"rendered":"https:\/\/kienzler-klima.de\/?p=997675"},"modified":"2026-08-19T11:28:59","modified_gmt":"2026-08-19T09:28:59","slug":"how-to-calculate-optimal-air-volume-flow-draft-free-hall-ventilation","status":"publish","type":"post","link":"https:\/\/kienzler-klima.de\/en\/how-to-calculate-optimal-air-volume-flow-draft-free-hall-ventilation\/","title":{"rendered":"How to calculate the optimal air volume flow for draft-free hall ventilation?"},"content":{"rendered":"<div class=\"vgblk-rw-wrapper limit-wrapper\">\n<p>The optimal air volume flow for draft-free hall ventilation is calculated by linking hall size, type of use, heat and pollutant loads, and the desired air exchange rate. The simplified formula is: <strong>Volume flow (m\u00b3\/h) = Room volume (m\u00b3) \u00d7 Air exchange rate (1\/h)<\/strong>. The air exchange rate itself depends heavily on the respective use and can range between 2 and over 20 per hour. The following sections explain each step of the calculation and show which mistakes you should avoid.<\/p>\n<h2>Which factors influence the air volume flow in a hall?<\/h2>\n<p>The air volume flow in a hall is determined by several physical and usage-related factors: room volume, heat load (from machines, people, or solar radiation), pollutant and moisture loads, and the required air quality. None of these factors acts in isolation \u2014 only their interaction yields the actually necessary volume flow.<\/p>\n<ul>\n<li><strong>Room volume:<\/strong> Floor area multiplied by the clear height gives the gross volume of the hall. For irregular floor plans or sloped roofs, the volume must be determined section by section.<\/li>\n<li><strong>Heat load:<\/strong> Machines, lighting, people, and solar inputs generate sensible heat that must be removed via ventilation. The higher the heat load, the greater the required volume flow.<\/li>\n<li><strong>Pollutant and moisture sources:<\/strong> In production halls, food processing facilities, or laboratories, gaseous emissions, dusts, or water vapor are added, significantly increasing the demand.<\/li>\n<li><strong>Number of occupants:<\/strong> For workplaces, ASR A3.6 specifies minimum outdoor air volume flows per person that must not be undercut.<\/li>\n<li><strong>Operating times and load variability:<\/strong> Shift operations, seasonal fluctuations, and varying occupancy require flexible design, often with variable-speed fans.<\/li>\n<\/ul>\n<h2>How is the air volume flow calculated step by step?<\/h2>\n<p>The air volume flow for hall ventilation can be calculated in four steps: determine the room volume, establish the air exchange rate, perform the heat load calculation, and select the largest of the determined values as the design parameter. This maximum value ensures that all requirements are met simultaneously.<\/p>\n<h3>Step 1: Room volume and air exchange rate<\/h3>\n<p>Multiply the floor area and clear height to obtain the hall volume in m\u00b3. Then select an appropriate air exchange rate for the intended use: for offices and commercial spaces, 2 to 6 air changes per hour are often sufficient; for production halls with heat or pollutant sources, it can be 10 to 20 or more. The first reference value is then: <em>V\u0307 = Volume \u00d7 Air exchange rate<\/em>.<\/p>\n<h3>Step 2: Heat load calculation<\/h3>\n<p>Determine the total heat load in watts (machines, people, lighting, solar inputs). The required cooling capacity via ventilation is derived from: <em>V\u0307 = Q \/ (\u03c1 \u00d7 c<sub>p<\/sub> \u00d7 \u0394T)<\/em>, where \u03c1 \u2248 1.2 kg\/m\u00b3 (air density), c<sub>p<\/sub> \u2248 1,005 J\/(kg\u00b7K) (specific heat capacity), and \u0394T is the permissible temperature difference between supply and exhaust air. Typical \u0394T values are 6 to 10 K.<\/p>\n<h3>Step 3: Establishing the design parameter<\/h3>\n<p>Compare the volume-flow-based value from Step 1 with the heat-load-based value from Step 2. The higher value is decisive. Additionally, consider the person-related minimum volume flows according to ASR A3.6 (at least 20 m\u00b3\/h per person in offices, up to 40 m\u00b3\/h in physically active areas). All three requirements must be met simultaneously.<\/p>\n<h2>What does draft-free mean and what outlet velocity is required?<\/h2>\n<p>Draft-free means that the air in the occupancy zone has a flow velocity of no more than 0.15 to 0.25 m\/s. Above this value, people perceive the air movement as an uncomfortable draft, leading to complaints and reduced productivity. The outlet velocity at the air diffuser itself must therefore be selected so that the air is sufficiently decelerated by the time it reaches the occupancy zone.<\/p>\n<p>Conventional slot diffusers or nozzles discharge air at velocities of 2 to 8 m\/s and use the momentum for mixing. This only works without drafts if the distance between the outlet and the occupancy zone is large enough. In low halls or with irregular floor plans, this is structurally challenging. <a href=\"https:\/\/kienzler-klima.de\/en\/textile-air-ducts-basics\/\">Textile air distribution<\/a>, on the other hand, works with outlet velocities of less than 0.5 m\/s across the entire sock surface, so that the air is virtually momentum-free at the point of exit and distributes evenly throughout the room.<\/p>\n<h2>How do textile and conventional air distribution systems differ at the same volume flow performance?<\/h2>\n<p>With the same air volume flow, textile air distribution systems distribute the air over a significantly larger outlet area than conventional sheet metal ducts with point diffusers. The result is a more uniform temperature distribution, lower flow velocities in the occupancy zone, and a permanently draft-free indoor climate without complex readjustment.<\/p>\n<ul>\n<li><strong>Outlet area:<\/strong> A <a href=\"https:\/\/kienzler-klima.de\/en\/countless-variation-options\/\">textile air sock<\/a> releases air across its entire permeable woven surface. Conventional systems concentrate the volume flow on a few outlets, creating locally high velocities.<\/li>\n<li><strong>Pressure loss:<\/strong> Textile systems operate at lower static pressure, which reduces the energy demand of the fans.<\/li>\n<li><strong>Installation and material costs:<\/strong> Compared to sheet metal duct systems, textile solutions can save up to 60% in material and installation costs, as no complex assembly of fittings and suspension structures is required.<\/li>\n<li><strong>Hygiene and cleaning:<\/strong> Textile socks are fully removable and machine washable, which is especially critical in the food industry and healthcare.<\/li>\n<li><strong>Appearance and flexibility:<\/strong> Textile systems can be color-customized and, due to their light weight, can also be used in existing buildings with limited load-bearing capacity.<\/li>\n<\/ul>\n<p>More information on the specific <a href=\"https:\/\/kienzler-klima.de\/en\/can-be-used-in-all-areas-and-industries\/\">applications of textile ventilation systems<\/a> can be found in our industry overview.<\/p>\n<h2>What mistakes are commonly made when calculating volume flow for halls?<\/h2>\n<p>The most common mistakes in volume flow calculation for halls are: heat loads set too low, failure to account for simultaneity factors, incorrectly chosen temperature differentials, and neglecting leakage in the duct network. These mistakes lead either to an undersized system with comfort problems or an oversized system with unnecessarily high operating costs.<\/p>\n<ul>\n<li><strong>Heat load underestimated:<\/strong> Machine heat, lighting, and solar gains are often only roughly estimated rather than accurately recorded through measurement or planning.<\/li>\n<li><strong>Simultaneity not considered:<\/strong> Not all heat sources are active at the same time. Adding all loads without applying simultaneity factors results in oversized planning.<\/li>\n<li><strong>Temperature differential set too high:<\/strong> An excessively high \u0394T assumption yields a calculated volume flow that is too low and insufficient in practice.<\/li>\n<li><strong>Leakage in the duct network ignored:<\/strong> Sheet metal ducts exhibit leakage of 5 to 15% depending on workmanship quality. Failing to account for this results in less volume flow at the outlet than calculated.<\/li>\n<li><strong>Flow behavior in the room not simulated:<\/strong> A correctly calculated total volume flow does not yet guarantee draft-free distribution. Without considering air guidance and outlet velocity, short-circuit flows or dead zones will occur.<\/li>\n<\/ul>\n<h2>When should a specialist planner be consulted for hall ventilation?<\/h2>\n<p>A specialist planner for hall ventilation should be consulted at the latest when the hall has a floor area of more than 500 m\u00b2, when special usage requirements such as clean rooms, food production, or hazardous material storage exist, or when official permits and documentation are required. In these cases, the complexity of the design exceeds the scope of rough rule-of-thumb calculations.<\/p>\n<p>Professional planning is also economically sensible for existing buildings with unknown building parameters, when retrofitting ventilation systems in ongoing operations, or when energy efficiency and funding requirements are involved. A qualified planner prepares a complete load calculation according to DIN EN 16798, selects the appropriate air distribution system, and documents the system so that future maintenance and expansion are straightforward.<\/p>\n<h2>How Kienzler Klima supports you with hall ventilation<\/h2>\n<p>We at Kienzler Klima accompany you from the first volume flow calculation through to the finished ventilation system. With more than 30 years of experience in textile air distribution and production exclusively in Germany, we know what matters in hall ventilation: precise design, draft-free air distribution, and a solution that is economically viable in the long term.<\/p>\n<p>Here is what we specifically offer you:<\/p>\n<ul>\n<li>Individual design of the air volume flow based on your hall data, type of use, and heat load structure<\/li>\n<li>Custom-made textile air socks with an average production time of just 14 days<\/li>\n<li>Up to 60% savings in material and installation costs compared to conventional sheet metal systems<\/li>\n<li>Cradle-to-Cradle certified products with permanently integrated, non-washable fire protection<\/li>\n<li>Competent consulting for planners, installers, wholesalers, and end customers alike<\/li>\n<\/ul>\n<p>Contact us: <a href=\"https:\/\/kienzler-klima.de\/en\/contact-us\/\">Submit your inquiry<\/a> and we will work together with you to develop the optimal solution for your hall ventilation.<\/p>\n<\/div>\n<p><!-- .vgblk-rw-wrapper --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculate air volume flow for large halls: a step-by-step guide to draft-free ventilation, including the most common planning mistakes.<\/p>\n","protected":false},"author":13,"featured_media":999688,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-997675","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-unkategorisiert"],"acf":[],"_links":{"self":[{"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/posts\/997675","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/comments?post=997675"}],"version-history":[{"count":1,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/posts\/997675\/revisions"}],"predecessor-version":[{"id":997744,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/posts\/997675\/revisions\/997744"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/media\/999688"}],"wp:attachment":[{"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/media?parent=997675"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/categories?post=997675"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kienzler-klima.de\/en\/wp-json\/wp\/v2\/tags?post=997675"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}