Explore chapters and articles related to this topic
Off-Gas Treatment
Published in Cristiane Q. Surbeck, Jeff Kuo, Site Assessment and Remediation for Environmental Engineers, 2021
Cristiane Q. Surbeck, Jeff Kuo
The volumetric air flow rate is commonly expressed in ft3/min, that is, cubic feet per minute (cfm), or m3/min. Since the volumetric flow rate of an air stream is a function of temperature and pressure, and the air stream undergoes zones of different temperatures and pressures in a thermal process, the air flow rate that is measured with instruments is the actual cfm (acfm). The unit of acfm refers to the volumetric flow rate under the actual temperature and pressure. The standard cfm (scfm) is the flow rate at standard conditions, that is, standard temperature and pressure. Standard pressure is always atmospheric pressure, that is, 1 atm or 14.7 psi or 101.3 kPa or 760 mm-Hg. However, the definition of the standard temperature is not universal. For the EPA, the standard temperature is T = 77°F (25°C). But 32°F (0°C) or 68°F (20°C) are also commonly used in technical articles as the standard temperature. One should follow the regulatory requirements and use the appropriate reference temperature for a specific project. A standard temperature of 77°F (25°C) is used in this chapter, unless otherwise specified.
Control of Organic and Inorganic Gaseous Emission
Published in Jeff Kuo, Air Pollution Control Engineering for Environmental Engineers, 2018
The volumetric gas flow rate is commonly expressed in ft3/min in the US customary system that is cubic feet per minute (cfm). Since the volumetric flow rate of an air stream is a function of temperature and the gas stream undergoes zones of different temperatures in a thermal process, the air flow rates are shown in actual cfm (acfm) or standard cfm (scfm). The acfm refers to the volumetric flow rate under the actual temperature and pressure, while scfm is the flow rate at the standard conditions. The standard conditions are the basis for comparison. Unfortunately, as mentioned earlier the definition of the standard conditions is not universal. For EPA’s documents related to combustion, the standard conditions are T = 77 °F (25 °C) and P =1 atm. Consequently, this standard temperature is used for combustion calculations here.
Design of Soil Vapor Extraction Systems
Published in Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen, Design of Remediation Systems, 2020
Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen
Conversion of SCFM to ACFM. The volume of air removed (as in SVE systems) or delivered (as in AS systems) by a blower is given in cubic feet per minute (CFM). This may be either CFM at actual temperature and pressure, actual cubic feet per minute (ACFM), or at standard temperature and pressure, standard cubic feet per minute (SCFM). ACFM refers to the actual quantity of air moved, taking into consideration the local effects of temperature and pressure. SCFM refers to the flowrate measured at atmospheric pressure and a standard temperature of 70°F (some manufacturers use 68°F). (For utmost accuracy, SCFM also requires correction to a standard humidity of 36 percent.)
Coplanar capacitive sensors and their applications in non-destructive evaluation: a review
Published in Nondestructive Testing and Evaluation, 2023
T. Zhu, K. Wen, Z. Zhang, X. Yuan, W. Li, X. Yin
In response to the ever-increasing pressure to meet safety requirements, various Non-destructive Evaluation (NDE) techniques, including visual inspection (VI) [1] [2,3], ultrasound testing (UT) [4–7], radiography testing (RT) [8–10], magnetic particle testing (MP) [11,12], magnetic flux leakage testing (MFL) [13–15], infrared radiation thermography testing (IRT) [16,17], eddy current testing (EC) and alternating current field measurement (ACFM) [18–23] have been developed to identify potential hazards, damage and/or defects present in the environment, commodities manufactured and structures constructed in a bid to ensure safety [24]. The various capabilities, limitations, advantages and disadvantages of these NDE techniques can be found in [25–30].