{"id":580,"date":"2026-10-21T21:19:35","date_gmt":"2026-10-21T13:19:35","guid":{"rendered":"http:\/\/www.jemakucarpet.com\/blog\/?p=580"},"modified":"2026-10-21T21:19:35","modified_gmt":"2026-10-21T13:19:35","slug":"what-is-the-humidity-resistance-of-a-pressure-transmitter-45d1-743568","status":"publish","type":"post","link":"http:\/\/www.jemakucarpet.com\/blog\/2026\/10\/21\/what-is-the-humidity-resistance-of-a-pressure-transmitter-45d1-743568\/","title":{"rendered":"What is the humidity resistance of a pressure transmitter?"},"content":{"rendered":"

If you\u2019re working in industrial automation, process control, or even HVAC systems, you\u2019ve probably relied on a pressure transmitter at some point. But here\u2019s a question that doesn\u2019t come up as often as it should: what\u2019s the deal with its humidity resistance? As someone who\u2019s been supplying pressure transmitters for over a decade, I\u2019ve lost count of how many times a customer has called me panicking because their unit failed in a damp environment\u2014condensation buildup, high ambient humidity, maybe even occasional rain. That\u2019s why humidity resistance isn\u2019t just a spec on a datasheet; it\u2019s what separates a transmitter that runs for 5+ years from one that dies in 6 months. Let\u2019s break this down like we\u2019re chatting in a break room, no jargon overload. Pressure Transmitter<\/a><\/p>\n

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First, let\u2019s get the basics straight: humidity resistance for a pressure transmitter is its ability to keep working accurately, and not corrode, when exposed to moisture in the air. Not all moisture is the same, though. There\u2019s high ambient humidity (like 95% RH in a paper mill or food processing plant where steam\u2019s constantly running), condensation (when a cold transmitter hits warm, humid air\u2014hello, pipe surfaces and outdoor installs), and even occasional direct water exposure (like a transmitter on a wastewater plant aeration tank). Each of these puts different stress on the device, and that\u2019s why a one-size-fits-all spec doesn\u2019t cut it.<\/p>\n

I see so many customers skip over this spec when buying a transmitter\u2014they fixate on pressure range (0-100 psi, 0-10 bar) or output signal (4-20 mA, HART), and just check the \u201chumidity\u201d box for \u201cstandard.\u201d But here\u2019s the thing: standard humidity resistance (usually around 85% RH at 40\u00b0C, no condensation) works for dry labs or air-conditioned control rooms. Put that same unit in a brewery\u2019s fermentation room, where humidity hovers at 98% and the temperature swings 10\u00b0C every hour? You\u2019re gonna have issues. Most failures I\u2019ve fielded early on weren\u2019t from pressure overload\u2014they were from moisture seeping into the housing, shorting the circuit board, or corroding the pressure sensor diaphragm.<\/p>\n

Let\u2019s talk about how transmitters handle moisture, because that\u2019s where the real engineering happens. Every good pressure transmitter has a hermetically sealed sensor core\u2014meaning the sensitive parts (the diaphragm, the piezoresistive elements that turn pressure into an electrical signal) are sealed inside a housing that doesn\u2019t let water or vapor in. But \u201chermetic\u201d isn\u2019t a guarantee, especially for budget models. The housing\u2019s O-rings, cable glands, and vent filters are the weak points. Wait, vent filters\u2014yeah, I know, they sound counterintuitive. Transmitters need a vent to equalize pressure between the inside and outside of the housing, so changes in atmospheric pressure don\u2019t throw off readings. But that vent also lets moisture in if it\u2019s not a special desiccant vent filter. A desiccant filter absorbs water vapor, so air can pass through, but moisture can\u2019t build up inside the housing. That\u2019s a key feature I push to customers\u2014skip the basic vent, go for a desiccant one, especially for high-humidity environments.<\/p>\n

Then there\u2019s the material of the housing itself. Stainless steel is common, but not all stainless is the same. 316L stainless is better than 304 for corrosive moisture\u2014like in chemical plants where humidity has trace amounts of acids or salts. Plastic housings might work for low-humidity indoor uses, but they can\u2019t handle UV or extreme condensation, so outdoor or coastal installs? Stick to metal. I had a customer a few years back who installed plastic-housed transmitters on a coastal jetty\u2014within 3 months, the housing was cracking and corroding from salt humidity. Switched to 316L units, they\u2019ve been running fine ever since.<\/p>\n

Now, let\u2019s get into the failure modes that matter. When moisture gets into a transmitter, the first thing that usually happens is condensation on the sensor diaphragm. That distorts the diaphragm\u2019s shape, so it doesn\u2019t measure pressure accurately\u2014you\u2019ll get noisy readings, or readings that drift over time. Next, if moisture hits the circuit board, it can cause a short circuit, which kills the unit outright. Even worse, if there\u2019s salt in the humidity (like in a marine setting), it can start corroding the metal traces on the board or the sensor\u2019s internal connections. Corrosion is a slow killer\u2014you might not see it for a year, but by then the sensor\u2019s already degraded beyond repair.<\/p>\n

I want to clarify a common misconception: humidity resistance isn\u2019t just about high RH numbers. It\u2019s also about temperature cycling, because that\u2019s what causes condensation. Let\u2019s say a transmitter is installed outside, where the temp drops to 0\u00b0C at night, then jumps to 30\u00b0C during the day. The cold housing cools the air inside, which condenses into water. If the desiccant filter can\u2019t keep up with that rapid moisture buildup, you get a pool of water inside the housing. That\u2019s why units designed for outdoor high-humidity use have to pass a temperature cycling test with humidity\u2014usually -40\u00b0C to 85\u00b0C, with humidity that reaches 100% RH (condensing). A lot of cheap transmitters claim \u201chumidity resistant\u201d but only pass the static 85% RH test, not the cycling one. I always advise customers to ask for the test details, not just the spec number.<\/p>\n

Another point: IP ratings, which are often confused with humidity resistance. IP67, for example, means a device is dust-tight and can withstand immersion in water up to 1m for 30 minutes. That\u2019s great if your transmitter gets splashed, but it doesn\u2019t tell you how it handles sustained high humidity or condensation. A transmitter could be IP67 but fail a 100% RH cycling test in 2 weeks. So don\u2019t mix those up\u2014IP is for water ingress from direct exposure, humidity resistance is for airborne moisture over time.<\/p>\n

Let\u2019s talk about real-world examples. Take a food processing plant\u2014they have washdowns multiple times a day, so humidity is high, and there\u2019s occasional direct water. The transmitters here need to not just handle high RH, but also be resistant to water that has food oils or cleaning chemicals. I supply units with 316L housings, desiccant vents, and conformal coating on the circuit boards. Conformal coating is a thin layer of polymer that protects the board from moisture and chemicals\u2014another feature that\u2019s worth the extra cost. I had a customer in a cookie factory who initially used uncoated boards; after 6 months, their transmitters were failing because of sugar dust mixing with humidity on the board. Switched to coated ones, no issues since.<\/p>\n

What about indoor high-humidity environments, like a hospital laundry room or a data center\u2019s cooling system? Here, humidity is high but not as extreme as industrial sites, but you still need reliable readings. For these, I recommend transmitters with at least 95% RH resistance, no condensation required, and maybe a conformal coating to prevent dust buildup mixing with moisture. I\u2019ve seen customers try to save money by using low-spec units here, but then they have to replace them every 12 months, which ends up being more expensive than buying a good one that lasts 5 years.<\/p>\n

Now, how do you choose the right humidity resistance for your application? Let\u2019s walk through a quick checklist, since I do this with every customer:<\/p>\n

    \n
  1. What\u2019s the ambient humidity in your installation? If it\u2019s over 90% RH, go beyond standard specs. If it\u2019s 90% and there\u2019s temperature cycling, go for a condensing humidity rating.<\/li>\n
  2. Is there corrosive moisture? Look for 316L housing, maybe a coating.<\/li>\n
  3. Is the transmitter exposed to direct water? Check IP ratings in addition to humidity specs.<\/li>\n
  4. What\u2019s your downtime cost? If shutting down a process costs $10k an hour, don\u2019t skimp on the humidity resistance.<\/li>\n<\/ol>\n

    I\u2019ve seen way too many customers go for the cheapest transmitter, only to regret it when it fails. Last year, a chemical plant called me in a panic because their transmitters were failing every 3 months. They\u2019d bought units from a overseas supplier that advertised \u201chumidity resistant\u201d for a fraction of my price. When we opened one up, there was water inside the housing\u2014turns out the vent filter was just a plastic mesh, no desiccant, and the O-rings were made of cheap rubber that degraded in 6 months. Switched to my units, which have desiccant filters and EPDM O-rings that handle high humidity and chemicals, they\u2019ve had zero failures since.<\/p>\n

    So here\u2019s the bottom line: humidity resistance isn\u2019t a \u201cnice-to-have\u201d feature, it\u2019s a critical one for any transmitter that\u2019s not in a controlled, dry environment. It\u2019s not just about surviving moisture\u2014it\u2019s about keeping accurate readings, which is the whole point of a pressure transmitter. If your readings are off because of moisture, you might end up with overpressure in a pipe, a process shutdown, or even safety hazards. That\u2019s not worth cutting corners for.<\/p>\n

    <\/p>\n

    Now, if you\u2019re out there looking for a pressure transmitter that\u2019s built to handle whatever humidity your environment throws at it\u2014whether it\u2019s a damp basement, a coastal industrial site, or a washdown-heavy food plant\u2014we\u2019ve got you covered. We build our transmitters with desiccant vents, corrosion-resistant materials, and conformal coatings, and we test every unit for humidity resistance under real-world conditions, not just in a lab. No cheap gimmicks, just reliable performance that lasts. So if you want to chat about your application, figure out the right humidity spec for your needs, or get a quote, reach out to us. We\u2019re here to help you avoid those unnecessary failures and keep your processes running smoothly.<\/p>\n

    \n

    Temperature Transmitter<\/a> References<\/p>\n

      \n
    1. Process Pressure Measurement: Humidity and Corrosion Effects, ISA \u2013 International Society of Automation, 2022.<\/li>\n
    2. Pressure Transmitter Environmental Testing Standards, IEC 60770-2:2019, International Electrotechnical Commission.<\/li>\n
    3. Conformal Coating Guidelines for Industrial Electronics, NEMA Standard IEC 60068-2-60, National Electrical Manufacturers Association.<\/li>\n
    4. Humidity Resistance for Industrial Sensors, Control Engineering Magazine, Vol. 45, No. 12, 2021.<\/li>\n<\/ol>\n
      \n

      Iges Instrument Co., Ltd.<\/a>
      With abundant experience, we are one of the most professional pressure transmitter suppliers in China. Please feel free to buy high quality pressure transmitter in stock here and get quotation from our factory. Good service and low price are available.
      Address: No. 103, 1st Floor, Dacheng Commercial Building, Chezhan Avenue, Lucheng District, Wenzhou City
      E-mail: igesinst@gmail.com
      WebSite:       https:\/\/www.iges-inst.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

      If you\u2019re working in industrial automation, process control, or even HVAC systems, you\u2019ve probably relied on … What is the humidity resistance of a pressure transmitter?<\/span>Read more<\/a><\/p>\n","protected":false},"author":335,"featured_media":580,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[543],"class_list":["post-580","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-pressure-transmitter-4913-75026b"],"_links":{"self":[{"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/posts\/580","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/users\/335"}],"replies":[{"embeddable":true,"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/comments?post=580"}],"version-history":[{"count":0,"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/posts\/580\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/posts\/580"}],"wp:attachment":[{"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/media?parent=580"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/categories?post=580"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.jemakucarpet.com\/blog\/wp-json\/wp\/v2\/tags?post=580"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}