Ventilation ducting

Cup anemometers have shaped cups mounted on the spokes of a wheel. The cups, under the action of the fluid forces, spin in a horizontal plane about a vertical shaft mounted in bearings. Vane or propeller types use a multibladed rotor, the axis of which is parallel to the flow direction as the rotating member. Both designs are commonly used for wind speed measurement or similar appHcations such as the velocity in ventilation ducts. Because of inertia, anemometers are most accurate under steady conditions. Velocity fluctuations cause readings that are too high. 

Detailed Includes the follow ing subtasks detailed design of ventilation Duct design... 

The above is valid for a liquid flow, when the effect of compressibility can be ignored when calculating gas flows with small pressure differences. For instance, in ventilating duct work, air is not compressed, so the density is considered as constant. In HVAC technology a unit of pressure frequently used for convenience is a water column millimeter, 1 mm H.O=10Pa. 

The use of tracers for airflow measurement in ventilation ducts is not very common. There are several reasons for this. Compared to other flow measurement methods, tracers require more complicated equipment, skilled personnel, and are more expensive. There are, however, situations when conventional measurement methods are not applicable. For instance, if the space available is small, and hence the flow meter cannot be installed, or if no space is free to carry out traversing measurements, the use of a tracer might be an alternative. 

High pressure steam lines Low pressure steam lines Vacuum steam lines Compressed air lines Refrigerant vapor lines High pressure Low pressure Refrigerant liquid Brine lines Ventilating ducts Register grilles... 

For the heat transfer for fluids flowing in non-circular ducts, such as rectangular ventilating ducts, the equations developed for turbulent flow inside a circular pipe may be used if an equivalent diameter, such as the hydraulic mean diameter de discussed previously, is used in place of d. 

Process errors led to discharge of copious amounts of nitrous fumes into the glass reinforced plastic ventilation duct above a diazotisation vessel. On two occasions fires were caused in the duct by vigorous reaction of the dinitrogen tetraoxide with nitroaniline dusts in the duct. Laboratory tests confirmed this to be the cause of the fires, and precautions are detailed. 

The ventilation rate in the fume hood and ventilation duct is approx 15 liter of air per seconds. The experiments have been performed with instrumentation at The Swedish Institute for Hood Technology Research. 

Figures 5a and 5b, respectively, show representative values for the incident shock and the leakage shock passing the blast valve. This loading was then used to analyze the ventilation ducting to assure no damage would occur.

Method for Determination of the Fire Resistance of Ventilation Ducts. 

Duct detector Is located within the heating and ventilation ducts of the facility. This sensor detects the presence of smoke within the system s return or supply ducts. A sampling tube can be added to the detector to help span the width of the duct. 

B. Glycine t-hutyl ester. In the center neck of a SOO-ml. suction filtration flask is placed a gas-inlet tube which is connected to a nitrogen cylinder, and on the side arm of the flask there is attached an exit tube leading to a suitable ventilation duct. The flask is placed on a magnetic stirrer, and a solution of 28.9 g. (0.18 mole) of /-butyl azidoacetate in 150 ml. of methanol and 0.7 g. of 5% palladium-on-charcoal catalyst is added to the flask. A stream of nitrogen is swept over the surface of the stirred suspension for 5 minutes, the nitrogen cylinder is replaced by a... 

Smoke infiltration may result from natural leakage openings (e.g., around ventilation ducting/grills), open doors, or breached fire barriers. The integrity of... 

Morrison, G. C., W. W. Nazaroff, J. Alejandro Cano-Ruiz, A. T. Hodgson, and M. P. Modera, Indoor Air Quality Impacts of Ventilation Ducts Ozone Removal and Emissions of Volatile Organic Compounds, J. Air Waste Manage. Assoc., 48, 941-952 (1998). 

Brattice driers, incorporating a device for removing the dried material (Fig. 44) have been used in Germany. The moist material, spread in a thin layer over cloth stretched on wooden frames (1), is dried in warm air supplied via the ducting (2) at a rate of about 0.5 m/sec. Next to the frame on which the material is dried there is a tin funnel (3) with a built-in sieve in its base. This funnel is connected with the ventilating duct by a flexible tube. Each frame (7) contains about 1.2 kg of fulminate (dry substance). To dry a batch of fulminate at 65-70°C takes... 

HVAC Materials Ventilation duct liners also react with ozone forming formaldehyde, acetone and C5—Ci0 aldehydes. Morrison et al. (1998) subjected new and used duct liners, air filters, sealants, sheet metal and other HVAC materials to ozone in small chambers. They observed secondary emissions of C5—Ci0 aldehydes from a new duct liner, a neoprene gasket and duct sealants. They predicted that secondary emissions from these materials could increase indoor aldehyde concentrations to levels comparable with odor thresholds. As will be discussed later, soiled HVAC materials also generate secondary products. 

Indoor air quality impacts of ventilation ducts ozone removal and emissions of volatile organic compounds. Journal of the Air sj Waste Management Association, 48 (10), 941-52. 

Table 5.2. Plutonium aerosols in ventilation ducts ofUSAECplants (Elder etal., 1974)...

We face a similar problem with the zinc-plated covers allegedly used to cover the ventilation ducts of the supposed gas chambers their exact origin and history is unknown. It would have been much preferable for the Cracow Institute to have analyzed samples from the walls of the alleged gas chambers instead of obtaining samples from pieces of metal ... 

The ventilation ducts of morgue 1 are visible in the plans published by J.-C. Pressac, op. cit. (note 67), pp. 224, 289 chapter on the ventilation installations of crematoria II and III ibid., pp. 355ff. engine power of the ventilation installations for all rooms in crematoria II and III ibid., p. 374 and 377 size of the ventilation outlets ibid., p. 234 Fig. of an outlet cover in the ventilation outlets. 

In addition to the ventilation duct the lid is equipped with two feed pipes, one for acids, (6), and one for the substance to be nitrated, (7), a thermometer sleeve (8), a delivery pipe for compressed air (9) and a pipe (10), reaching down to the bottom, for discharging the nitrator contents by means of compressed air. It is essential to furnish the lid with a manhole (II). During nitration, the manhole opening is closed by a thin sheet of aluminium, which at the same time plays the role of a safety valve in case the pressure should rise inside the vessel. 

Medical Sources. All medical encapsulations are done in a facility which consists of a series of five interconnected stainless steel boxes which provide primary containment of process equipment and materials. Interconnections include transfer ports, drop-through tubes, and ventilation ducts. Each containment enclosure has a floor area of 1.52 m x 0.91 m the floor level is 0.76 m above the building floor. A pair of master-slave manipulators serve each containment box. A closed circuit television system and a telescope are provided for close-up viewing of incell operations and can be moved from cell to cell as needed. General arrangement of the facility is shown in Figures 13 and 14. 

Thermoplastic Piping Systems Plumbing Systems Municipal Piping Industrial Piping Systems Ventilation Duct Systems Fire Protection Systems... 

C In one of the hotter regions of the country a home owner decides to keep her home at an average temperature of 80°F and 40 percent humidity. On a typical day the outside conditions are as follows dry-bulb temperature = 95°F and wet-bulb = 85°F. The city water supply is at 70°F and scarce. She therefore decides to use an electric refrigeration unit to cool the air entering the ventilating ducts. Summary of conditions ... 

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