Exhaust ductwork

Exhaust ductwork not properly sealed 6. Small concentra- I C 2 tions CSM in the workplace possible in the event the exhaust system were to go positive. Personnel injury or death possible. System/facility damage minimal. Scenario less likely due to additional requirement for system to go positive. 

A final consideration in selecting a mixture of power generation or direct drive prime movers is exhaust ductwork. If a platform is surrounded by gas-combustion turbine drivers exhausting vertically, hot gases may create hazards at some wind conditions. Ductwork may need to be run Irom the exhaust to platform edge this should be minimized to assist area classification, helicopter landing patterns, and expense. 

Ductwork within building All exhaust ductwork inside the building should be under negative pressure... 

Air cleaning devices Where possible, air-cleaning devices should be located close to the process to avoid contamination of exhaust ductwork. Bag in/bag out (safe-change) filters or comparable required for all filtration systems... 

One of the most crihcal performance characterishcs of the commercial boiler burner is a level of green house emissions such as nitric oxides and carbon monoxide. The combushon product is typically sampling from the exhaust porhon of the test setup (laboratory) or exhaust ductwork (field) and then is being prepared (cooled, dried, filtered) and forwarded to the appropriate gas analytical equipment. Figure 19.8 illustrates the set of the analyhcal equipment typically used for the burner testing at the GTI Applied Combushon Research Facility. 

Zone 1 Ventilation System SSSSC Ventilation supply and exhaust ductwork connected to each SCB. 

A) Exhaust ductwork shall be adequately supported throughout its length to sustain its weight plus any normal accumulation in interior during normal operating conditions and any negative pressure exerted upon it. 

B) Exhaust ductwork shall be sized in accordance with good design practice which shall include consideration of fan capacity, length of duct, number of turns and elbows, variation in size, volume, and character of materials being exhausted. See American National Standard Z9.2-1960 for further details and explanation concerning elements of design. 

Exhaust ductwork shall be adequately supported and sized. 

The components of fume hoods can be divided into four categories the supporting base cabinet, the chamber interior, the hood face (consisting of the sash and unit front), and the exhaust ductwork and fan. Each of these components is important in either the proper use of the hood or in its efficiency, or both. 

The operation of flow dampers can cause pressure fluctuations in the ductwork system. Measurements by Melin indicate that pressure oscillations in an exhaust system can cause instabilities in the airflow through a fume cupboard sufficient to give rise to outward leakage of contamination, especially when a person stands in front of the cupboard. 

Manifold A section in the exhaust air ductwork of an air treatment system into which exhaust air enters from a number of orifices or ducts, or a header pipe in a fluid flow system that has branches. 

Due to the amount of water vapor produced when natural gas is burned, it is important not to allow the exhaust gas temperature to fall below 80°C, otherwise the water dewpoint will be reached. Not only the economizer but also the ductwork and chimney must be considered and provision incorporated for drainage. 

Hoods usually have a light built into a sealed opening, making it explosion-proof for use with flammables. Fans used for flam-mables must also be explosion-proof. Those used for corrosive fumes must be made of material resistant to such fumes. The ductwork must also be corrosion resistant, a matter often overlooked. Built-in exhaust fans make installation and servicing easy, but some tend to be noisy. Remotely installed fans are generally quieter and may serve more than one hood. The chief problem with fans is that they are often improperly serviced. Lubrication and belt tightness must be checked as specified by the manufacturer, or costly repairs will result. 

Minimum Duct Velocity. Once the types and locations of hoods, enclosures and booths have been established and the exhaust rates determined, it is necessary to design the ductwork to transfer the contaminated gas to the collection or cleaning device. An essential parameter required for this purpose is the minimum duct or conveying velocity, Vfmm, which is required to ... 

After an exhaustive investigation, it was determined that the cause of the nonuniform tablets was segregation in the tote/overhead feeding system used in the manufacturing operation. The laboratory- and intermediate-size batches were hand-scooped into the hopper of the tablet press. The overhead-feed duct acted as a classifier. The differences in cohesion and adhesion of the two actives, coupled with the length and angle of the ductwork, fostered segregation. 

Gases are forced through the cylinder by either an exhauster or an exhauster-blower combination. With the latter arrangement it is possible to maintain very precise control of internal pressure even wlien the total system pressure drop is high. When a low-pressure-drop air heater is employed, however, the exhauster alone is usually sufficient, as the major gas pressure losses are found in the exit-air ductwork and dust collectors. Use of a blower by itself to force gas through the cylinder is an unusual practice, because the internal pressure is above atmospheric and hot air and dust may be blown into the gas seals or out into the surrounding working areas. 

Personnel injury This interlock is to prevent injury due to entering the dryer during operation, but more typically to prevent dryer start-up with personnel in the main chamber or inlet or exhaust air ductworK on large dryers. This typically involves microswitches on access doors coupled with proper door lock devices and tags. 

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