Сколько весит куб лиственницы естественной влажности: Сколько весит куб лиственницы, вес куба доски из лиственницы

Вес куба лиственницы естественной влажности. Сколько весит куб сырой доски из сосны – Сколько весит один сухого и влажного дерева, пригодного для строительства

Наглядно можно заметить, что обрезанная доска в поперечном сечении имеет форму правильного прямоугольника. Данный факт отличает ее от необрезанной доски. Благодаря столь важной особенности, ее можно ровно укладывать в штабеля, правильно упаковывать и определить объем упакованных материалов. Если необходимо будет определить, сколько весит куб доски, достаточно будет перемножить плотность и объем. Следует отметить, что плотность является величиной справочной, которая зависит как от породы древесины, так и от ее влажности.

Какое воздействие оказывает влажность на вес древесины?

Влажность оказывает непосредственное влияние на вес пиломатериалов и прочих изделий из дерева. Как известно, она измеряется процентным отношением массы воды в древесине к массе сухой древесины. Следует заметить, что влажность зависит еще и от условий сушки, ее продолжительности и подразделяется на следующие степени:

• Сухая — древесина, которая обязательным образом прошла технологическую сушку и имеет влажность от 10% до 18%.
• Воздушно-сухая — древесина с равномерной влажностью от 19% до 23%, степень которой можно достичь, если хранить древесину в естественных условиях.
• Сырая — древесина с показателем влажности от 24% до 45%, которая находится на стадии высыхания.
• Свежесрубленная и мокрая — древесина, имеющая влажность более 45%, только срубленная или находящаяся продолжительное время в воде.

Следует заметить, что показатель веса древесины не всегда одинаковый. Поэтому то, сколько весит куб доски, зависит, в первую очередь, от такого параметра, как влажность дерева. Если в качестве примера взять дуб и березу, то можно заметить, что кубический метр дуба имеет вес в 700 кг, а березы — около 600 кг. Однако может быть и наоборот, то есть значение березы будет больше, нежели дуба. Подобные показатели имеют место, потому что в данном случае немаловажное значение занимает влажность древесины. Исходя из категорий влажности, можно сказать, несмотря на одинаковую влажность, каждая порода древесины имеет свой вес.

Влияние плотности на весовую категорию

Плотность является еще одним немаловажным фактором, влияющим на вес древесины. Как правило, наиболее высокой плотностью обладает железное и черное дерево, показатели которых варьируются от 1100 кг/м3 до 1350 кг/м3. Более близкие цифры могут представить самшит и мореный дуб — от 950 кг/м3 до 1100 кг/м3. Прежде чем рассчитать, сколько весит куб доски дуба, бука, груши или граба, следует учитывать их плотность, которая составляет приблизительно 700 кг/м3. Наименьшей плотностью отличается сосна и бамбук — 500 кг/м3, ну, а самый мизерный показатель имеет пробковое дерево — 140 кг/м3.

Для чего необходимо знать вес кубического метра древесины?

Знать, сколько весит куб доски естественной влажности, порой бывает очень необходимо. Вед

90000 How Much Does a Cloud Weigh? 90001 90002 As convenient as smartphones and tablets are, they do not necessarily offer the best sound quality. But a well-built portable speaker can fill that need. And whether you’re looking for a speaker to use in the shower or a device to take on a long camping trip, these bestselling models from Amazon have you covered. 90003 90004 1. OontZ Angle 3 Bluetooth Portable Speaker; $ 26- $ 30 (4.4 stars) 90005 90002 Of the 57,000-plus reviews that users have left for this speaker on Amazon, 72 percent of them are five stars.So it should come as no surprise that this is currently the best-selling portable Bluetooth speaker on the site. It comes in eight different colors and can play for up to 14 hours straight after a full charge. Plus, it’s splash proof, making it a perfect speaker for the shower, beach, or pool. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 2. JBL Charge 3 Waterproof Portable Bluetooth Speaker; $ 110 (4.6 stars) 90005 90002 This nifty speaker can connect with up to three devices at one time, so you and your friends can take turns sharing your favorite music.Its built-in battery can play music for up to 20 hours, and it can even charge smartphones and tablets via USB. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 3. Anker Soundcore Bluetooth Speaker; $ 25- $ 28 (4.6 stars) 90005 90002 This speaker boasts 24-hour battery life and a strong Bluetooth connection within a 66-foot radius. It also comes with a built-in microphone so you can easily take calls over speakerphone. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 4. Bose SoundLink Color Bluetooth Speaker; $ 129 (4.4 stars) 90005 90002 Bose is well-known for building user-friendly products that offer excellent sound quality. This portable speaker lets you connect to the Bose app, which makes it easier to switch between devices and personalize your settings. It’s also water-resistant, making it durable enough to handle a day at the pool or beach. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 5. DOSS Soundbox Touch Portable Wireless Bluetooth Speaker; $ 28- $ 33 (4.4 stars) 90005 90002 This portable speaker features an elegant system of touch controls that lets you easily switch between three methods of playing audio-Bluetooth, Micro SD, or auxiliary input.It can play for up to 20 hours after a full charge. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 6. Altec Lansing Mini Wireless Bluetooth Speaker; $ 15- $ 20 (4.3 stars) 90005 90002 This lightweight speaker is built for the outdoors. With its certified IP67 rating-meaning that it’s fully waterproof, shockproof, and dust proof-it’s durable enough to withstand harsh environments. Plus, it comes with a carabiner that can attach to a backpack or belt loop. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 7.Tribit XSound Go Bluetooth Speaker; $ 33- $ 38 (4.6 stars) 90005 90002 Tribit’s portable Bluetooth speaker weighs less than a pound and is fully waterproof and resistant to scratches and drops. It also comes with a tear-resistant strap for easy transportation, and the rechargeable battery can handle up to 24 hours of continuous use after a full charge. In 2020 року, it was Wirecutter’s pick as the best budget portable Bluetooth speaker on the market. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 8.VicTsing SoundHot C6 Portable Bluetooth Speaker; $ 18 (4.3 stars) 90005 90002 The SoundHot portable Bluetooth speaker is designed for convenience wherever you go. It comes with a detachable suction cup and a carabiner so you can keep it secure while you’re showering, kayaking, or hiking, to name just a few. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 9. AOMAIS Sport II Portable Wireless Bluetooth Speaker; $ 30 (4.4 stars) 90005 90002 This portable speaker is certified to handle deep waters and harsh weather, making it perfect for your next big adventure.It can play for up to 15 hours on a full charge and offers a stable Bluetooth connection within a 100-foot radius. 90003 90002 90009 Buy it: 90010 Amazon 90003 90004 10. XLEADER SoundAngel Touch Bluetooth Speaker; $ 19- $ 23 (4.4 stars) 90005 90002 This stylish device is available in black, silver, gold, and rose gold. Plus, it’s equipped with Bluetooth 5.0, a more powerful technology that can pair with devices up to 800 feet away. The SoundAngel speaker itself is not water-resistant, but it comes with a waterproof case for protection in less-than-ideal conditions.90003 90002 90009 Buy it: 90010 Amazon 90003 90002 90085 This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links. 90086 90003 .90000 How Much Does a Cloud Weigh? 90001 90002 90003 • Water Science School HOME • Water Basics topics • The Water Cycle • Water Properties topics • 90004 90005 90006 How much does a cloud weigh? 90007 90008 90002 90010 We will use math instead of a giant weight scale to calculate the weight of a cumulus cloud. 90011 90005 90002 Do you think clouds have any weight? How can they, if they are floating in the air like a balloon filled with helium? If you tie a helium balloon to a kitchen scale it will not register any weight, so why should a cloud? To answer this question, let me ask if you think air has any weight-that is really the important question.If you know what air pressure and a barometer are, then you know that air does have weight. At sea level, the weight (pressure) of air is about 14 ½ pounds per square inch (1 kilogram per square centimeter). 90005 90002 Since air has weight it must also have 90003 density 90004, which is the weight for a chosen volume, such as a cubic inch or cubic meter. If clouds are made up of particles, then they must have weight and density. The key to why clouds float is that the density of the same volume of cloud material is less than the density of the same amount of dry air.Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is less dense than dry air. 90005 90002 We still need to answer the question of how much a cloud weighs. To confuse things more, the weight depends on how you define it: 90005 90021 90022 The weight of the water droplets in the cloud 90023 90022 The weight of the water droplets plus the weight of the air (mostly above the cloud, pressing down) 90023 90026 90002 We’re only going to look at the weight of the actual cloud particles.One estimate of cumulus cloud density is given at 90028 https://www.sciencealert.com/this-is-how-much-a-cloud-weighs 90029, as a density of about 0.5 gram per cubic meter. A 1 cubic kilometer (km 90030 3) 90031 cloud contains 1 billion cubic meters. 90005 90002 Doing the math: 1,000,000,000 x 0.5 = 500,000,000 grams of water droplets in our cloud. That is about 500,000 kilograms or 1.1 million pounds (about 551 tons). But, that «heavy» cloud is floating over your head because the air below it is even heavier- the lesser density of the cloud allows it to float on the dryer and more-dense air.90005 90002 90003 ► 90004 90028 The little cloud that could-but why? 90029 (Why does this cloud exist?) 90005.90000 How Much Does the Moon Weigh? 90001 90002 What do you do if you encounter an alien? It’s obviously fairly unlikely, but nothing is impossible-after all, you can not spell 90003 meet 90004 without 90003 ET 90004. If there’s a stray dog ​​in your backyard, there’s a set procedure to follow. But what if, rather than a mere hound, it’s a creature from another world? 90007 90002 «If you meet an alien in your backyard, my recommendation is to get out of town,» Seth Shostak, senior astronomer at the SETI Institute, an organization seeking to explore, understand, and explain the origin and nature of life in the universe , tells Mental Floss.»If they have the technology to come here, they’re so far beyond us that whatever they want to do, they’re going to do. If they’re here to take over the planet, it’s going to be pretty hard to stop them. » 90007 90002 A creature from another planet lurking on your property means not only that there is intelligent life elsewhere, but that it is at a significantly more technologically advanced stage than humanity. A species with the ability to not only travel the enormous distances involved (the closest star to our sun, which does have some potentially life-supporting planets, is 4.2 light years away), but also land undetected in your flowerbed would simply have us outclassed. 90007 90002 As you flee, however, you might want to contact the emergency services. If, for instance, the alien is aflame-and given that we know nothing about what form such a creature might take, there’s no real reason it 90003 would not 90004 be-you might want to give the fire department a call, for example . Moving up a notch, the FBI and Department of Defense are frequently contacted with flying saucer sightings, as are the UK’s Royal Air Force and Ministry of Defence and, well, pretty much every other emergency service in every country.This is because there is no set protocol, no universally agreed-upon decree of exactly what to do in the event of a close encounter. 90007 90002 «As far as I know, there is no policy for that, because that would be like Neanderthals having a policy for if the U.S. military decided to take them on, «Shostak says. «If aliens were actually landing here, we could have whatever policy we wanted and it would not be likely to help much.» 90007 90002 Whatever Hollywood might tell us, the likelihood is that any contact we have with beings from another world will be limited to picking up a signal from deep space, rather than encountering the long fingers and warm heart of a charming 3-foot-tall alien rustling around in shrubbery.As luck would have it, there 90003 is 90004 a protocol for that; it’s known as the Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence [PDF] and was put together by the International Academy of Astronautics with input from Shostak. 90007 90002 The protocols are also entirely voluntary, with no force of law behind them and nobody under any obligation to adhere to them. What if you do not 90003 want 90004 to tell everybody? What if you fancy keeping information about life beyond Earth to yourself for a while? You’re the one talking to aliens, after all-surely you can make a few bucks out of the situation… 90007 90002 As Shostak points out, this kind of thinking is unlikely to get you anywhere. Given the distances involved, and the power required to transmit information that far, you are not going to be in any kind of dialogue. Secondly, revealing that you have detected a transmission is useless without it being verified and studied-the process of which, by necessity, involves making that information available to the world. Thirdly, interpreting any alien message will be a mammoth task involving a lot of work from a lot of people, a task unlikely to ever reach a definitive conclusion.»It would depend on whether they were trying to make it easy,» Shostak says. 90007 90002 Anything you discovered would belong to humanity as a whole, as we collectively tried to figure out what the signal meant, both literally and existentially, knowing we are not alone in the universe. You’d get to be the first person to prove there was intelligent life beyond Earth, which might be mildly less exciting in the short term than getting attacked by a little green man while taking the trash out, but at least you’d live to tell the tale.90007 .90000 What Are Acceptable Moisture Levels in Wood? 90001 90002 Understanding Moisture Content in Wood 90003 90004 How Does Moisture Affect Wood? 90005 90006 90007 Everyone who works with wood needs to understand how wood interacts with moisture in the environment. Whether you’re a woodworker making cabinets, a wood flooring professional installing hardwood floors, or if you use wood in construction, 90008 wood moisture content (MC) 90009 should be always on your mind.90010 90006 Wood is hygroscopic. It gains or loses water moisture as the relative humidity (RH) of the surrounding air changes. 90010 90006 These varying humidity levels of the surrounding air cause wood to not only gain or lose water moisture but to expand or shrink as well. As the humidity increases, the MC increases, causing the wood to expand. As the humidity decreases, the MC decreases, causing the wood to shrink. When the wood neither gains nor loses moisture, we say that the wood has reached its equilibrium moisture content (EMC).90010 90006 According to Dr. Eugene Wengert, professor and specialist in wood processing at the University of Wisconsin-Madison’s Department of Forestry, wood should be dried to a water MC that’s within two percentage points of the EMC where the wood is going to be used. 90010 90006 Before we explain what this means, let’s make sure we have our definitions down. 90010 90019 90020 MC = the wood’s moisture content 90021 90020 The EMC (equilibrium moisture content) of the location where the wood is at the moment or the location of where the wood is going to be used = the MC that the wood will eventually attain if it’s placed in that location.90021 90024 90006 If this is confusing, do not worry. The chart below will clear things up. Notice that the EMC of the in-use location is the 90008 same 90009 as the MC: 90010 90029 90030 90031 90032 Humidity of the in-use 90033 location 90033 90035 90032 EMC of the in-use location 90035 90032 Corresponding MC the wood will attain at this location 90035 90040 90041 90042 90031 90044 19-25% 90045 90044 5% 90045 90044 5% 90045 90040 90031 90044 26-32% 90045 90044 6% 90045 90044 6% 90045 90040 90031 90044 33-39% 90045 90044 7% 90045 90044 7% 90045 90040 90031 90044 40-46% 90045 90044 8% 90045 90044 8% 90045 90040 90031 90044 47-52% 90045 90044 9% 90045 90044 9% 90045 90040 90083 90084 90006 So, using this chart, we know that in an area of ​​the country where the RH inside a home or office is anywhere from 26-32%, both the EMC of the in-use location and the wood moisture content kept in that location will be 6%.90010 90006 This means that wood intended for interior use in this location should not only be dried to around 6% but should be kept at this moisture content both before and during the manufacturing process. 90010 90006 So, the wood must always be allowed to acclimate or come into balance with the RH of the end-use location. Failure to do this will result in warping, cracking, and other problems after the construction of the wood product. 90010 90002 How Do You Remove Moisture From Wood? 90003 90004 Kiln Drying 90005 90006 Freshly cut wood has a lot of moisture in it.Eventually, this internal moisture will evaporate by itself. However, kiln drying is used to speed up the process. Some of the unfinished wood you see on the market has been kiln-dried to reduce its water moisture content to around 8% so that it will not suffer from moisture-related defects like warping and buckling. However, many building materials may have been dried down to about 15% moisture content. 90010 90006 But, that’s not the end of the story … 90010 90006 Wood moisture content is always varying.It’s never constant. Wood — freshly cut or kiln-dried — is always interacting with environmental moisture. Therefore, just because the wood is kiln-dried does not mean it has lost the ability to absorb moisture. It will continue to absorb and release moisture until it comes into balance with the surrounding air. 90010 90002 What are Acceptable Moisture Levels in Wood? 90003 90006 The acceptable moisture levels of wood and lumber are in the range of 6% to 8% for interior and 9% to 14% for exterior wood or for building envelope components within constructed assemblies.The acceptable moisture content in wood depends on two factors: 90010 90019 90020 The wood’s final use. 90021 90020 The average RH of the environment where the wood will be used. 90021 90024 90006 These two factors make it difficult to say anything specific about acceptable wood moisture content. It’s more important to understand that the wood is kiln-dried down to a certain bell-shaped 90008 range 90009 of MCs. There will be statistical outliers on both the low and the high end and you’ll want to catch these by using a quality moisture meter.90010 90002 How to Measure Moisture Content in Wood? 90003 90006 There are two main ways of measuring wood moisture content: oven-dry testing and moisture meter testing. Let’s go over the basics of each … 90010 90004 1. Oven Dry Testing 90005 90006 Oven dry testing is the oldest method for measuring the moisture content of wood. The process is time-consuming but produces accurate results if followed correctly. Here’s how it works … 90010 90006 The wood sample being tested is dried in a special oven or kiln and its weight periodically checked.Once the wood sample’s weight stops changing, its weight is compared to what it was before the drying process began. This weight difference is then used to calculate the wood’s original moisture content. 90010 90006 While oven-dry testing, if followed correctly, offers accurate results, there are a few drawbacks: 90010 90019 90020 90008 It takes a long time 90009 — We’re talking about hours. The oven drying process must be done slowly or the wood could burn and the test results will be worthless.90021 90020 90008 It will render the wood unusable 90009 — It often happens that oven drying over dries the wood to the point where it’s unusable. 90021 90020 90008 It requires a special oven or kiln 90009 — Most hobbyists who work with wood do not have an oven that’s capable of producing accurate results. 90021 90024 90006 These three drawbacks mean that oven-dry testing usually is not the option of choice for hobbyists who work with wood. 90010 90004 2. Moisture Meter Testing 90005 90006 The fastest way to test the moisture content of wood is to use a moisture meter.There are two main types of wood moisture meters, pin-type and pinless. 90010 90147 Pin-type Wood Moisture Meters 90148 90006 Pin-type meters use penetrating electrodes and measure the wood’s moisture content using electrical resistance. Since water conducts electricity and wood does not, the dryness of the wood can be determined by the amount of resistance to an electrical current. Dryer wood produces more resistance than wetter wood. 90010 90147 Pinless Wood Moisture Meters 90148 90006 Pinless meters are non-penetrating and read the moisture content via a non-damaging electromagnetic sensor that scans the wood.Because pinless meters scan the wood’s surface and cover a larger area than pin-type meters, they provide a more thorough picture of the wood’s moisture content. 90010 90006 Pinless meters also do not leave damaging pinholes on the wood’s surface. This makes pinless moisture meters perfect for measuring the moisture content of things like expensive hardwood floors. 90010 90002 How to Measure Moisture Content in Wood with a Moisture Meter? 90003 90004 Pin-Type Moisture Meters 90005 90006 The general process for using pin-type moisture meters is as follows … 90010 90019 90020 Insert the pins into the surface of the wood you want to test.90021 90020 Make sure they’re aligned with the grain and not across it. 90021 90020 Turn on the meter. The electrical current will then move from pin to pin and measure the resistance encountered. 90021 90024 90004 Pinless Moisture Meters 90005 90006 Pinless moisture meters are even easier to use. Just press the scanning plate against the wood’s surface, turn on the meter, and receive the reading. 90010 90006 Shop Wood Moisture Meters 90010 90002 How Accurate Are Wood Moisture Meters? 90003 90006 The ASTM D4442 standard determines the accuracy of wood moisture meters.This method uses the oven-dry method and then compares the results to those obtained using a moisture meter. The difference is the moisture meter’s measurement error. 90010 90006 For more information, see our article comparing Pinless Moisture Meters vs. Pin Meters. 90010 90002 Moisture Content of Wood from a Woodworker’s Perspective 90003 90006 Because wood shrinks and warps as it dries, woodworkers want it to be pre-shrunk before they use it. Furniture maker Lonnie Bird weighs in, 90010 90006 «I do not want the wood to shrink after I use it because the wood will warp or split.»90010 90006 Bird, who runs the School of Fine Woodworking outside Knoxville, Tennessee, says he knows wood shrinks seasonally but wants to minimize the shrinkage and expansion by drying the wood to a moisture content of about 8%. 90010 90006 To make sure the wood is properly dried, he always uses a moisture meter before working with it. 90010 90006 The moisture content of freshly cut wood is typically somewhere between 40-200%. If you’re wondering how wood can have a 200% moisture content, here’s how that works … 90010 90006 Because the moisture content of wood is equal to the weight of the water in the wood divided by the weight of the wood without the water, it’s possible for the moisture content to exceed 100%.In other words, the water weighs more than the wood fibers. 90010 90004 How Dry Should Wood Be for Woodworking? 90005 90006 The normal moisture content of wood (or EMC) varies from 7% -19% depending on the RH in the air. 90010 90006 For woodworkers who build cabinets, fine furniture, musical instruments, dishes, toys, decorative art, boat restoration, or various other wood products, the acceptable wood moisture content normally ranges from 6% to 8%. 90010 90006 However, this range will vary slightly according to the geographic region because of varying RH levels.90010 90006 If an interior location has an average RH of 40-52%, wood placed there will have an average EMC of 8-9%. This is based on a chart in Wood Handbook: Wood as an Engineering Material. 90010 90006 Therefore, in order to avoid post-construction problems, a woodworker building a cabinet for this particular interior environment would need to dry his wood to a moisture content of 8- 9% beforehand and then 90008 keep it that dry 90009 during the construction process . 90010 90006 The best way to do this is to use an accurate moisture meter.90010 90002 Moisture Content of Wood from a Flooring Installer’s Perspective 90003 90006 The National Wood Flooring Association (NWFA) has specific installation guidelines for wood flooring and how they relate to moisture content. 90010 90006 When determining the acceptable moisture levels in wood flooring before installation, the NWFA states that the flooring professional should establish a baseline for acclimation. Acclimation is the process for conditioning the moisture content of wood flooring to the environment where it will be installed.90010 90006 To establish a baseline for wood flooring acclimation, the installer will need to calculate the optimal moisture level of the wood by dividing the region’s high season and low season EMC. For example, if the expected EMC ranges from a low of 6% to a high of 9%, the baseline moisture content of the wood would be 7.5%. 90010 90006 The installer should then check the moisture content of multiple boards and average the results. A high reading in one area indicates a problem that must be corrected.90010 90006 We really can not overstress the importance of taking plenty of moisture readings. When you do this, you not only ensure that the entire batch is okay on average, but you’re also far likelier to catch boards that are statistical outliers and could cause problems. 90010 90006 If the moisture content of the product is well outside the range of optimal MC, the wood flooring should not be accepted because it will lead to shrinkage, bowing, cupping, and other physical problems. 90010 90006 For example, if the moisture content of the delivered wood is 12% and the optimal MC is 6%, then physical problems will occur during the acclimation process.90010 90006 90230 To avoid this problem, wood flooring should never be stored where environmental conditions are uncontrolled, such as garages and exterior patios. 90010 90006 As a general rule, with geographic exceptions, wood flooring performs best when the interior environment is controlled to stay within an RH range of 30% to 50% and a temperature range of 60 to 80 degrees Fahrenheit. However, the ideal humidity range in some climates may be higher or lower. For example, from 25% to 45% or from 45% to 65%.90010 90006 The National Wood Flooring Association (NWFA) has a chart that indicates the moisture content of wood at any given combination of temperature and humidity. The EMC in the recommended temperature / humidity range coincides with the 6% to 9% range used by most flooring manufacturers during the manufacturing and shipping process. Although some movement can be expected between 6% and 9%, wood flooring can shrink or swell more dramatically outside this range. 90010 90006 Installers should also measure the moisture in wood subfloors and concrete slabs as they can also affect wood flooring.The maximum subfloor moisture level for solid strip flooring or wide-width solid flooring is either 12% or 13%, depending on the manufacturer. 90010 90006 The National Association of Home Builders ‘Green Home Building Guidelines for solid strip flooring and wide-width flooring are as follows: 90010 90019 90020 For solid strip flooring (less than 3 «wide) there should be no more than a 4% difference in moisture content between properly acclimated wood flooring and subflooring materials. 90021 90020 For wide-width solid flooring (3 «or wider), there should be no more than a 2% difference in moisture content between properly acclimated wood flooring and subflooring materials.90021 90024 90002 Moisture Content of Wood and Lumber from a Builder’s Perspective 90003 90006 For most areas of the United States, acceptable moisture levels of wood and lumber can be in the range of 9% to 14% for exterior wood or for building envelope components within constructed assemblies. An MC in this range, therefore, is considered sufficiently dry for exterior in-service wood. 90010 90006 Using wood with a moisture content above 14% is not recommended because it may have detrimental long-term effects on the construction.90010 90006 In fact, according to M. Steven Doggett, Ph.D. LEED AP, the founder of Built Environments, Inc., wood moisture content as high as 15% can cause corrosion of metal fasteners and at 16% may lead to fungal growth. 90010 90006 When it comes to the moisture content of plywood or dimensional lumber, an MC of 17% to 19% reduces the overall strength of plywood, and an MC of 20% or more reduces the strength of dimensional lumber (ie, lumber cut to certain predefined sizes, such as 2x4s).90010 90006 A study by Imamura and Kiguchi (1999) showed that wood moisture content in excess of 20% can cause a 5% loss of nail shank diameter in four years and a projected 25% loss in 30 years. The same study showed a 40% loss in joint strength and concluded that a 20% MC may significantly compromise shear resistance of exterior walls. 90010 90006 When exposed to a constant RH, the moisture content of wood or lumber will come to equilibrium with its environment, resulting in an EMC for that species of a wood-based composite.90010 90006 The EMC of wood or lumber exposed to an outdoor atmosphere varies across the U.S. For instance, in the coastal city of Seattle, the EMC of wood or lumber is higher than the EMC of cities inland or in the Southwest. 90010 90006 Seattle’s EMC ranges from 12.2% to 16.5%. In the Midwest, the EMC of wood or lumber in Des Moines, Iowa, ranges from 12.4% to 14.9%. 90010 90006 In contrast, Las Vegas in the drier Southwest has much lower EMC percentages than most other U.S. cities. The Las Vegas EMC of wood or lumber ranges from 4.0% to 8.5%. 90010 90002 Acceptable Moisture Levels for Wood In a Nutshell 90003 90006 Based on common guidelines or recommendations, the acceptable moisture levels for wood are as follows: 90010 90019 90020 Wood objects used indoors: 6-8% 90021 90020 Wood flooring: 6-9% 90021 90020 Construction: 9-14% 90021 90024 90006 Keep in mind that a wood’s acceptable moisture level will depend primarily on 90008 how 90009 it will be finally used and the average RH 90008 where 90009 it will be finally used.However, the wood species and the thickness or size of the wood may also factor in. 90010 90006 In all cases, determining the acceptable moisture level of wood requires the use of an extremely accurate moisture meter. 90010 90006 Failure to allow the wood to acclimate or come into balance with the RH at its end-use location could result in any number of moisture-related problems after the wood product is constructed. These include warping, cracking, buckling, diminished wood strength, corrosion of fasteners, and even fungal growth.90010 90288 90006 Larry Loffer is a senior technician at Wagner Meters, where he has over 30 years of experience in wood moisture measurement. With a degree in Computer Systems, Larry is involved in both hardware and software development of wood moisture measurement solutions. 90010 .