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Gandhi [98,99] performed some simple modeling of three types of gas collections systems that could be used in corrosion tests, the CNET test, the cone corrosimeter, and a third system that utilized a piston cylinder chamber. He used the mass fraction of an arbitrary corrosive component of the fire effluent, a, as an indicator of how each capture system works and Smoke Damage Restoration Tips developed design parameters for each test. 

However, the important quantity for determining corrosivity is the concentration. The non dimensionalized concentration measures for the three tests are also developed in Appendix C. For the CNET test, Smoke Damage Restoration Tips the concentration is much easier than the mass fraction and is simply(7)where Ca*is the non dimensionalized concentration, is the non dimensionlized time, ya is the production rate of product a in units of kg of product a produced per kg of fuel burned and f*is a non dimensionlized mass loss rate. 

Thus, at the end of the burning phase of the CNET test, the concentration of product a is dependent on the amount of product a produced by the material being tested. With one caveat, Smoke Damage Restoration Tips there is a very straightforward relationship between the test material and the concentration of a particular corrosive product. 

The caveat is that there is concern about the mass loss rate being limited by the available oxygen.To show how serious the concern about oxygen limited combustion is, Smoke Damage Restoration Tips assume that the oxygen lower limit is 15.5 %, then the maximum sample size that can undergo complete combustion given the stoichiometric oxygen to fuel ratio is calculable as shown in Figure 13. 

Note that the non dimensionalized mass of a test material in ISO 11907-2 is 1.0. A number of common materials Smoke Damage Restoration Tips could experience oxygen limited burning in the CNET test so some care must be taken with interpreting the results of the test. Modeling the cone corrisometer Gandhi makes two significant simplifications. 

The first is to assume that the test uses mass flow control instead of volume flow control and Smoke Damage Restoration Tips that the control is sufficiently good to maintain constant mass in the exposure chamber. The second is not so much a simplification as a potential for misunderstanding. Gandhi assumes that the amount of mass entering and leaving is related to the mass loss rate (MLR) by a fraction f. 

While there is no requirement for f to be a constant it is easy to make that mistake. To make the analysis easier, it is desirable to consider a constant mass flow (see details in Appendix C). Since the volume is constant and the assumption is the mass is also constant, Smoke Damage Restoration Tips then the mass fraction of product a.

Ya, is also the non dimensionalized concentration and is given by (8)where fin*is the non dimensionalized mass flowing into and out of the exposure chamber, Ya is the fraction of the mass in the exposure chamber that is product a and Smoke Damage Restoration Tips is the rate of the mass of air entrained by the fire to the MLR. 

The term represents the fraction of the total flow of mass, both effluent and entrained air, Smoke Damage Restoration Tips generated by the test sample in the cone. This term will overestimate the fraction of the mass flowing into the exposure chamber at points where the total mass flow from the product is less than the forced flow of the pump, but should not be a significant error.

The fifth paper by the PFPC compared the results of the four standards and performed extensive analysis [79]. They reviewed the entire project and Smoke Damage Restoration Tips then did an overall analysis of the results.They looked at three factors in the comparison and analysis:1. Precision – Is the test repeatable? Does the test differentiate corrosive potentials? 

2. Accuracy – Does the test differentiate corrosive potential consistent with known chemistry? Are the test results consistent with existing standards?3. Cost, availability and convenience – Is the test equipment accessible, easy to operate and mechanically sound? To assess repeatability, Smoke Damage Restoration Tips they looked at the average coefficient of variation (the standard deviation divided by the mean expressed as a percentage), as well as the standard deviation of the coefficient of variation. 

Their results are given in Table 8. Clearly the indirect tests were the most repeatable of all the tests. None of the direct tests had a particularly low average coefficient of variation. The question becomes Smoke Damage Restoration Tips are they sufficiently repeatable. To answer this question they used two statistical tests to see how many statistically differentiated groups each test could break the 24 products into. 

CNET differentiated product 20 into one group, product 19 into a second group and the rest into a final group. Overall, Smoke Damage Restoration Tips they found that none of the four test methods satisfied all the criteria for a useful corrosion test. Since the tests did not give the same rankings they were not interchangeable. They recommended that both the cone corrosimeter and the radiant panel needed to have their repeatability improved and that development on the CNET test should stop. 

Use of Smoke and Species Yields as Model Inputs While there are detailed combustion models available that fully address gas-phase chemistry, Smoke Damage Restoration Tips they are not practical for the large domains encountered in typical fire scenarios. As such,modeling of chemistry in most current computer fire models is not considered in detail beyond a one-step effective reaction and is largely a bookkeeping exercise based on a simple reaction of fuel and oxygen such as shown below [100].

For complete combustion of the simplest hydrocarbon fuel, methane reacts with oxygen to form carbon dioxide and water. The only input required is the pyrolysis rate and Smoke Damage Restoration Tips the heat of combustion. For fuels that contain oxygen, nitrogen, or chlorine, the reaction becomes more complex. 

In this case, the user specifies model inputs for the composition of the fuel and a nynon-ideal combustion yields (such as the production of soot or Smoke Damage Restoration Tips carbon monoxide) to allow the model to calculate the mass of species produced during combustion. 

Most typically, these are specified as molar yields (i.e., the number of moles of a given species produced per mole of fuel consumed in the combustion reaction), Smoke Damage Restoration Tips though other normalized values are also used 5. For example, for soot, the effective molar yield, νS, is related to the soot yield, yS, via the relation where Wf and WS are the effective molar mass of the fuel and soot, respectively. In most cases these are idealized estimates for actual complex fuels.

OSHA Regulations For Perimeter Fencing

The NHC official forecasts did outperform many of the individual intensity models.Only the GHMI (at the 96 and 120 h periods) and the FSSE (at the 72-120 h periods) had smaller errors than the official intensity forecasts. However, Emergency Board up OSHA Regulations For Perimeter Fencing the intensity model consensus (ICON)bested the offici  read more..

Ceiling Leak From Storm

Coastal A zones are not shown on present day Flood Insurance Rate Maps (FIRMs) or mentioned in a community's Flood Insurance Study (FIS) Report. Those maps and studies show zones VE, AE, and X (or older designations V1-30, A1-30, B, and C). Therefore, until Coastal A Zone designations Structural Drying Ceiling Leak From Storm   read more..

Commercial Building Drying And Mold

MOLD/WATER DAMAGED MATERIALS Key Engineering Controls and Work Practices Discard all water-damaged materials, materials that are visibly coated with mold that cannot be properly cleaned, such as porous materials (e.g., carpeting, drywall, insulation), and Structural Drying Commercial Building Drying And Mold materials that have been wet   read more..

Basement Water Damage

The best way to face any Basement Drying Basement Water Damage problem is to first, do the obvious things, you know the things that are easy and least expensive. Then continue in a rational order doing the next least expensive thing with the most positive result. With a basement moisture problem, the best way to start is alw  read more..

Water Lead Test

If your residence was built prior to 1978, have your residence tested for Lead Paint Removal Water Lead Test and learn about potential lead dangers. Fix any dangers that you might have. You could get your residence checked for in one or both of the following methods: 

A house paint inspection — this tell  read more..

How To Clean Sewage Leaks Under A Mobile Home

Valves installed in sewer lines sometimes become "jammed" with debris and fail to close completely. If this is the case, the valve may slow down the backflow of sewage, Sewage Cleanup How To Clean Sewage Leaks Under A Mobile Home but not stop it completely. For this reason, a valve installed on a sewer line should not be depended upon for 100% protection  read more..

Mold Mitigation

These Structural Drying Mold Mitigation tracks are traits of Douglas-fir, pines, spruces and larches and are readily visible to your naked eyes, or under a low power magnifier on the end grains of planks and logs. In ponderosas, white and sugar pines, resin tracks are obviously visible as thin, brown stripes on the surfa  read more..

The Hazards Of Dealing With Lead Paint

Lead accumulates in the body following exposure. Lead stays in the blood for several months, and it can be stored in the bone for many decades. Lead poisoning (plumbism) usually results from many small exposures over a period of weeks or years. The brain and nervous system are particularly Lead Paint Removal The Hazards Of Dealing With Lead Paint  read more..

How To Clean Fire Damaged Walls

More and more people are making their homes in woodland settings - in or near forests, rural areas, Fire Damage How To Clean Fire Damaged Walls or remote mountain sites. There, homeowners enjoy the beauty of the environment but face the very real danger of wildfire.Every year across our Nation, some homes survive - while many others do n  read more..

Tornado Chasers Causing Damage

Mesovortices While storm downdrafts likely account for the greater proportion of damaging nontornadic winds in a derecho-producing convective system, observational evidence and numerical simulations show that corridors of enhanced wind damage in derecho-producing squall lines often are associated wi  read more..