Engineering Living Walls
LiveWall is an engineered living wall solution which is structurally sound, uses the highest grade components, and actually grows healthy plants.
Structural Loading Calculations
LiveWall planters weigh from 10-15 lbs/SF when fully grown and watered. To assist you with determining whether your structure can tolerate this load, we have commissioned an engineer to calculate the vertical gravity loads and lateral wind loads of the LiveWall vertical garden product.
This structural report provides equivalent wall pressure, maximum bending movement and equivalent uniform wall pressure.
Wind Pressure and Green Walls
Functionally, LiveWall can be placed as high as your building infrastructure, plumbing, and ability to access it for maintenance will allow. But, as with any siding, high wind can pose a threat to the security of an outdoor living wall siding. The LiveWall System provides excellent wind stability when properly installed. To do this, a review of wind pressure and associated variables, such as the building’s geographic location, surrounding terrain, shape, slope, height, openings, and other features is essential.
For starters, one must consider the typical high wind speeds for the installation site. Consult your region’s ASCE 7.95 Figure 6-1 Basic Wind Speed, or FM Approval Standard for Class 1 Exterior Wall Systems. In addition, the structural engineer must consider the natural forces on the building site; for example, is the building situated along water, mountains, or in an open field, and do tall trees or taller buildings surround it? Each of these factors can create a channeling force to intensify wind pressure against a structure.
Of course the building design itself is very important. Low rise buildings, generally regarded as 60 feet or lower, are less affected by a given wind load than buildings that are 60 feet and taller, which may experience substantial uplift forces in addition to direct/positive wind pressure.
Wind accelerates as it passes over a wall, causing a pressure differential and uplift, that is exerted on any living wall design. Redirected winds of this nature tend to whirl and swirl, and such forces are typically greatest at the edges of the wall but vary with building shape and height, overall exposure, size of openings, and other local factors.
Functionally, LiveWall can be placed as high as your building infrastructure, plumbing, and ability to access it for maintenance will allow. It is up to the discretion of the Owner/Architect/Engineer as to the appropriateness of the system at any given height, with all health, safety, and environmental factors to be considered.
Keep in mind that the taller the building, the more substantial the wind forces, particularly upward lifting wind forces. We recommend the use of limiting screws and our proprietary WindClip™ on living wall planters mounted more than 20′ from ground level. In regions prone to hurricanes or other high wind storms, we recommend using WindClips and limiting screws on all planters.
For more information, consult our engineering section.
On outdoor walls, the higher up you go, the windier the conditions tend to be, and you will get more evaporative drying. To compensate for this additional loss, adjust to run the irrigation longer on the upper zones. You can expect to lose about ½ PSI of pressure per each foot of elevation. This corresponds to about ½ PSI for each tier of the LiveWall system and on very tall walls, booster pumps may be needed to sustain pressure. Plumbing should be sized and engineered accordingly.
LiveWall Structure Code-Compliant on High-Wind Applications
In March 2016, UL LLC tested the LiveWall Structure according to TAS-202 “Criteria for Testing Impact and Nonimpact Resistant Building Envelope Components using Uniform Static Air Pressure,” Section 1619 of the Florida Building Code. The structure passed the Uniform Static Air Pressure Test at exterior (positive) and interior (negative) design pressures of 105 PSF.
These findings provide designers, building owners and code officials with assurance that LiveWall systems are safe for use on tall buildings and in wind-prone regions. For example, a LiveWall system installed on a 500 foot tall building in Orlando, Florida would comply with building code requirements. The following calculated minimum design loads encompass inland (120 mph wind speed) and most coastal (150 mph wind speed) regions of North America.*
*LiveWall system is considered a sign attached to the wall of a building per section 29.4.2 of ASCE 7-10 “Minimum Design Loads for Buildings and Other Structures.” Calculated loads using maximum values per equation 30.3.1 for velocity pressure in Exposure C as referenced in Chapter 30 “Wind Loads for Components and Cladding” of ASCE 7-10.
Living Wall Fire Resistance
Like all vertical garden designs, LiveWall is a building facade system and is not designed to be fire resistant. The molded LiveWall planters, however, are rated at 780º F flashpoint and burn at 450º F. The soil is relatively nonflammable, and the plant flammability varies by species. For example, if fleshy succulent plants are used, they will help deter some threats of fire. If grasses are used, to reduce their flashpoint, they should not be allowed to dry out. Proper use of the LiveWall System keeps the WallTer wall planters properly saturated, helping to reduce the danger of plant fires.
Living Wall Irrigation Hookup
The LiveWall system comes with the RainRail® mounting tracks which serve as the irrigation conduit. LiveWall also packages the header piping, irrigation valves and fittings (each fitted with a 25psi pressure regulator), a screen filter, irrigation controller, and backflow preventer. LiveWall may also supply a liquid fertilizer injector or descaling housing and cartridge.
This “irrigation infrastructure” is fed by the irrigation mainline and blow-out fitting in areas of cold winter, as installed by owner or contractor.
The LiveWall System requires an irrigation feed that is capable of providing sufficient water volume and pressure for each irrigation zone. The backflow preventer should be hooked up to a feed line that is at least 25PSI, not to exceed 85 PSI. Pressures over 85 PSI may damage fittings and lead to leaks.
Each valve requires 8-10 gpm per valve (zone), regulated to 15psi pressure, via pressure regulators that are placed upstream of each valve. In some cases, a booster pump may be required to ensure that the upper valves receive sufficient pressure and flow to water the planter array evenly.
LiveWall quotes mainline irrigation components for each project, and this includes backflow prevention, irrigation controller, and a micron filter to keep any waterborne debris from plugging up the irrigation nozzles. Installation contractors must source pipe and fittings to connect mainline to the irrigation valves.
Descaling Cartridges Ensure Water Flow
Properly treated hard water poses no health risks and actually provides beneficial nutrients to LiveWall plants. However, buildup of calcium or iron scaling from untreated hard water can potentially impair the flow of water through the irrigation nozzles. The cost of treating hard water is not an expensive add-on to a LiveWall System installation.
In cases of hard water, use phosphate descaling system to prevent irrigation system blockage or failure. This can be purchased from LiveWall. Descaling cartridges should be replaced annually and can be reordered from LiveWall.
Very large projects (over 2000 square feet) may require additional treatment. On larger walls, an alternative chemical treatment system may be preferred. In these cases, LiveWall recommends CH2O, Inc.
For a free water test to determine the type of hardness, how much is in the water, and the cost of treating 10,000 gallons of your water, send them a sample.
LiveWall systems may be purchased with a fertilizer injector that is tied into the irrigation system.
The fertigation system injects a low dose of fertilizer each time your living wall is irrigated.
LiveWall supplies an organic liquid fertilizer concentrate that must be diluted prior to use. For more information, download the injector operation and dilution instructions.
Manual Slow Release Granular Fertilizer
Outdoor walls and hand-watered indoor walls may be fertilized once annually using a granular slow release fertilizer such as Scotts Osmocote®.
A single spring application is usually sufficient to feed plants through the growing season. Shake one teaspoon of fertilizer evenly across the soil surface of each full-width, Standard sized wall planter. Apply half as much for half-width Standard size planter and twice as much for Large planters.
Manual Liquid Fertilizer
Every 6 to 12 months, indoor or outdoor living walls which do not have automatic fertigation may be fed with a higher concentration of liquid feed.
Fertilizer may be applied manually according to the label directions using a watering can or a hose.
IMPORTANT: Do not use granular fertilizer for indoor walls with automatic irrigation. The granules require water to run over the surface to activate, and LiveWall indoor systems include drip stakes that inject water directly into the soil.
Application rates will vary with formulation. In all cases, follow directions on package label.
All applications of fertilizer are the sole responsibility of the applicator.