Filters:  #   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z   All

Vacuum Sampling The collection of surface matter through a vacuum. Vacuum collection devises can be special upright HEPA vacuums%u002C to small cassettes attached to a vacuum pump. After collection%u002C the vacuumed material is either field identified under a microscope or in a laboratory. See Air Sampling%u002C Adsorbent Sampling%u002C Bulk Material Sampling%u002C Soil Sampling%u002C Surface Sampling%u002C Swab Sampling%u002C Tape Lift Sampling%u002C Water Sampling%u002C Wipe Sampling   Validation An independent confirmation method determining that the services provided by the contractor were completed as agreed.   Validation Sampling A laboratory verification method substantiating that the water%u002C mould%u002C bacteria or chemical mitigation services provided by the contractor%u002C left no harmful effects behind. See Clearance Sampling   Valley Fever Valley Fever is also known as San Joaquin valley fever%u002C desert fever or desert bumps. The disease is called Coccidioidomycosis caused by the fungi Coccidioides immitis%u002C and not to be confused with the fungus disease Cryptococcus neoformans associated with pigeon feces. Valley fever was first identified in the San Joaquin valley in Central California. Valley fever is caused by a soilborne fungi%u002C that has resulted in farm and construction workers dying from inhalation of the fungi into their lungs. The fungi over recent years has come south through what is called the lower Sonora region of California into Los Angeles. Health and Safety Note%u003A Valley fever is mentioned because during the recent southern California earthquake of 1994%u002C much of the valley floor became exposed to the disturbance of airborne clouds%u002C including spores. California Contractor Note%u003A Emergency response and restoration contractors   Valuation The act of estimating or appraising. A process of valuing%u002C estimating or determining a value of a material or object. Valuation may take into account depreciation%u002C based on age or wear and tear.   Value Protection Clause In insurance terminology%u002C a value protection clause in an insurance policy may be provided when there is an increase in the limit of insurance applying to a specific coverage%u002C which reflect changes in costs of construction and personal property values. Any such increase will typically be made on the renewal date of the policy%u002C or on the anniversary date of 3-year policies paid annually.   Vapour Vapour in the strict sense is a gas. Moisture vapour is simply moisture in a gaseous form. Vapour has weight and mass which is measurable.   Vapour Barrier One of several acceptable material membranes used to prevent moisture and moisture vapour%u002C in transferring or penetrating through a vapour barrier. The membrane may be a 15 to 60mm thick plastic placed under the concrete slab%u002C or an asphalt treated material.   Vapour Emissions from Concrete Moisture vapour emission is a quantity of vapour %u0028or equivalent liquid water%u0029 emanating from a concrete slab over a period of time. Although vapor emission is influenced to some degree by temperature and humidity differentials%u002C the most important influence is the quality of the concrete %u0028as measured by permeability and porosity%u0029. The effect of vapour pressure on vapor emission is negligible.   Vapour Pressure and Vapour Emissions Moisture vapour pressure from concrete is the direct relationship between the moisture content in concrete and pressures forced on to the concrete. Vapour emissions is the result of escaping vapour from a material into air. Vapour pressure and vapour emission are related only to the extent that we are talking about the same vapor%u003B and the fact that each may be influenced by some of the same variables. Vapour emissions of water in the atmosphere is governed by%u002C and is directly related to temperature and humidity.   Vapour Pressure as Back Pressure In Concrete A misnomer and common conception%u002C that concrete appears to represent itself as having or producing a vapor back-pressure. Education Note%u003A Vapour pressure rises and falls according to the two variables of temperature and humidity. Vapour pressure is %u0022not%u0022 capable of accumulating or producing a %u0022build-up of trapped vapor pressure%u0022 The term %u0022back pressure%u0022 as it relates to vapor pressure in concrete probably came about in an attempt to explain the higher volume of moisture accumulation that may occur in the uppermost layer of concrete %u0028after covering it with a low-permeable%u002C or non-permeable flooring material or sealer%u0029. Moisture that collects in this fashion is usually due to improper concrete curing%u002C which has resulted in a surface with demonstrable higher permeability and porosity than the interior section of the concrete. The higher permeability and porosity of the surface allows a %u0022reservoir effect%u0022 to occur%u002C which will temporarily result in higher than normal vapour emission measurement after the floor covering is removed. The vapour pressure readings will return to %u0022normal%u0022 when the stored moisture is allowed to be expelled.   Vapour Pressure Charts The in an atmosphere%u002C vapour pressure charts are of temperature and humidity that calculate vapour pressure of moisture in pounds per square inch %u0028PSI%u0029.   Vapour Pressure in Floors Vapour pressure is roughly defined as the pressure caused by the energy of moving molecules of the vapour%u002C measured as vapour pressure.   Vapour Pressure in Floors over Concrete The amount of moisture as vapor pressure%u002C that emits through force from a substrate. Education Note%u003A As it relates to floors over a concrete substrate%u002C the vapor originates from moisture within the concrete itself. Vapour pressure of water in the atmosphere is governed by%u002C and is directly related to temperature and humidity. Vapour pressure from the floor is offset %u0028sometimes overcome%u0029 by vapour pressure within the space above the floor%u002C with a net pressure differential. Vapour pressure in a floor or concrete%u002C is a force %u0028per unit area%u0029%u002C independent of atmospheric surroundings of a room%u002C except for temperature and relative humidity.   Vapour Pressure Osmosis a%u0029 The diffusion or spreading of water through a membrane until they are mixed. b%u0029 Osmotic pressure is the pressure produced by the tendency of a relatively pure fluid to pass %u0028through a semipermeable membrane%u0029 into a relatively impure solution. Education Note%u003A In the case of floors%u002C the %u0022fluid%u0022 is water%u002C the %u0022semipermeable membrane%u0022 is concrete%u003B and the %u0022relatively impure solution%u0022 is moisture plus dissolved salts in the concrete. Although osmotic conditions are capable of creating problems that will become quickly apparent %u0028usually within a couple of weeks%u0029%u002C there is no evidence to support osmotic pressure as a primary cause of a floor failure. Water condensing under a flooring material from vapor emission is %u0022pure%u002C%u0022 and creates osmotic pressure as it is inclined to move toward %u0022impure%u0022 moisture in the concrete containing dissolved salts. The most extreme pressure to be expected in concrete is probably on the order of 8 to 10 p.s.i. The pressure created by osmotic pressure is relatively low%u002C and it will not normally disturb cured adhesives or damage concrete. See Moisture Related Flooring Failures   Vapour Transfer The ability of a vapor%u002C such as water vapor%u002C to transfer from one surface or atmosphere to another. Education Note%u003A Water vapour is a gas%u002C and it can diffuse and pass through porous building materials easily. Water vapour can also pass through a solid building material%u002C depending upon the difference in vapour pressure between the two sides of the solid material and the permeability of the material. Water vapour moves through solid materials at a rate proportionate to the difference in vapour pressure on either side of the material. The greater the vapour pressure on one side of a material%u002C the faster the other side will be affected. Mitigation Note%u003A In water damage mitigation%u002C especially when it comes to wet wall drying%u002C reducing the vapour pressure between wet walls or a wall cavity%u002C greatly influences the vapour pressure and its permeability factor. For example%u002C after drilling weep holes and aeration holes %u0028usually 3/8%u0022 to 2%u0022%u0029 in size%u002C drilled below the base board but above the mud sill or sill plate%u002C allowing for forced dehumidified air to enter and pressurize the wall cavity. The increased dry air vapour pressure will increase the vapour transfer rate which the wet wall material will become dry faster. See Permeability Factor%u002C Shear Walls   Vapourization of Fire Department Water During a building fire event%u002C the fire department uses large amounts of water from fire hoses to reduce and eliminate the flame and the flammable source. Contractor Note%u003A The heat from a fire in an enclosed atmosphere%u002C will allow a stream or spray %u0028fog%u0029 of water to expand up to 1%u002C700 times its mass from the waters original dispersion size. This results in liquid water to turn into steam water droplets%u002C then the droplets are changed into a moisture vapour state. %u0028With extremely hot-heat%u002C water from a fire hose immediately goes to the vapour state%u0029. With heat%u002C vapourized water and cooler building material surfaces%u002C the building materials absorb the water vapour rapidly%u002C and often the water vapour is actually forced into porous cells of the building matrix through advection and conduction. Dehumidification of a wet building from a hot-fire is complicated by the radical dispersion of vapourized moisture molecules in building materials%u002C along with the atmospheric stresses brought about from heated forces of increased air volume. See Absorption%u002C Advection   Veneer Covering A thin sheet of wood or composite material that was made to look like wood%u002C which is laminated on to the surface of a desk%u002C cabinet%u002C counter%u002C shelf for example. Education Note%u003A Veneer coverings can be sensitive to moisture and temperature%u002C and they may delaminate from the surface to which they are attached.   Vent An opening which air is allowed to pass through freely. Vents are part of a buildings natural air intake and exhaust system. Vents are common to basements%u002C crawlspaces%u002C plumbing%u002C attic and roof.   Ventilation for Acceptable Indoor Air Quality Ventilation for Acceptable Indoor Air Quality are the design%u002C engineering%u002C installation and maintenance of a heating%u002C ventilation and air-conditioning system as found in ASHRAE Standard 62-1989. The Ventilation for Acceptable Indoor Air Quality design requirements recommend 15 cubic feet of air per minute %u0028CFM%u0029 per person of fresh outdoor air into buildings.   Ventilation Systems The engineered%u002C designed and mechanical system of a building. Ventilation systems bring in fresh filtered air and they take out %u0028exhaust%u0029 used air. Energy efficient buildings have return air systems that allow filtered building air before it is sent back to the occupied building air space.   Ventiliating a%u0029 One of several methods acceptable to exhaust and get rid of gases%u002C vapors and airborne pollutants from a work space. One of the easiest methods%u002C is the use of exhaust fans pointed downwind from the outside air stream. b%u0029 A mechanical system of a building which allows the building to bring in fresh air and exhaust contaminated air.   Venturi Air Scrubber An air pollution control device that removes particulates%u002C vapours%u002C acid mists and gases from polluted air streams. The venturi effect is created at the throat of the narrow section of the duct%u002C called the venturi throat. The velocity of low air pressure increases in the duct as pressure builds towards the venturi throat%u002C and picks more up velocity as it passes the specially designed throat%u002C resulting in higher collection efficiency of pollutants.   Venturi Effect The increase of air velocity of a stream of air through a constriction or duct.   Vertical Window Framing The plumb%u002C straight and true framing of the rough window area that allows a window assembly to be installed properly.   VHS %u0028Vertical and Horizontal Spread%u0029 The VHS model considers a worst-case scenario and makes assumptions about the potential of further lateral and horizontal damage due to a contamination. The VHS model for water and sewage damages in a contaminated building for example%u002C results in a technician to consider potential unknown or hidden damage as part of the damage assessment and survey. The VHS model can be adopted to other damaged environments such as a fire damaged building or high-rise where smoke%u002C soot and water may have migrated. VHS in this case has been adopted from EPAs VHS model for hazardous environments.   Viable Viable means alive. The alive cells and spores of bacteria and protozoa%u002C fungi and yeasts%u002C that are alive %u0028and sometimes dormant%u0029%u002C which can be grown and reproduced in a laboratory. See Culturable%u002C Non-Culturable%u002C Non-Viable   Viable Fungi Colours When fungi and molds are alive they are multi-colored from red%u002C pink to orange. Some common examples are%u003A Black Color Fungi - Alternaria%u002C Chaetomium%u002C Ulocladium and Stachybotrys. Stachybotrys produces a very deep black to dark purple color. Green Color Fungi - Aspergillus and Penicillium species. When these species sporulate%u002C they turn a velvety green. The mycelia growth itself%u002C is typically white. White Color Fungi - Fusarium%u002C yeasts and mycelia growth%u002C indicating the start of mould growth or young non-sporulating growth%u002C such as identified on Acremonium%u002C Aspergillus and Penicillium%u002C during their youth growth cycle and before maturity.   Video Documentation The real-time documentation and 3-dimensional view of the environment or situation%u002C involving a claim or event. See Inventory   Video Inspection An electronic photographic representation or documentation of a claim or damage to a property through the use of video cameras. Video documentation allows for a 3-D presentation to be completed with voice to explain the content of the video.   Vinyl Flooring A resilient flooring system%u002C that is made in sheets or tiles. Vinyl flooring is composed of vinyl plastics%u002C binders%u002C mineral fillers%u002C color patterns%u002C and a scratch resistant coating.   Visible Fungi Contamination Visible fungi means that fungi which is observed on surfaces by the eye. For visible fungi to become noticeable to the average person%u002C millions of spores must be present in a collection. A surface area the size of a quarter can support tens to a hundred million fungal spores%u002C depending on spore type and size.   Voids Empty spaces in a building that are designed for no particular purpose%u002C such as an enclosed walled off area%u002C under the steps leading to another floor. See Pockets of Saturation   Volatile In water damaged buildings%u002C volatile describes water which evaporates or vapourizes in the air rapidly and at high temperatures.   Volatile Organic Compounds %u0028VOCs%u0029 A category of organic compounds with a relatively high vapour pressure%u002C which a majority are air contaminates. VOCs are carbon-hydrogen bonded compounds %u0028hydrocarbons%u0029%u002C but they also may be aldehydes%u002C chlorinated hydrocarbons%u002C ketones%u002C and other hydrocarbon-based compounds. VOCs are in paint%u002C carpet%u002C adhesives%u002C binders%u002C household cleaners%u002C film%u002C and materials that make up most of today%u0027s manufactured furniture. Excessive VOC exposure to some sensitized individuals produces an immediate health response and reaction to the VOC%u002C resulting in skin irritation%u002C nausea%u002C depression%u002C reactions to the central nervous system%u002C and/or an increased risk of cancer.   Volatility The tendency or ability of a liquid to vapourize. Such liquids as gasoline and alcohol%u002C because of their well-known tendency to evaporate quickly%u002C are called volatile liquids.   Volume of Air The amount of air in a given air space. See Air   V-Zone FEMAs coastal flood designation for portions of the 100-year floodplain subject to a storm-driven velocity of waves of three feet or more in height.