The global retail e-commerce sales was expected to grow to 4.88 trillion U.S. Dollars in 2021 from 2.3 billion U.S. Dollars in 2017, that’s a 111.72% increase in just 4 years. (eMarketer, 2018) (eMarketer, 2018). Grade Separation on Northpark Drive AM Peak Hour 2: Kingwood Dr. Lane Group EBL EBT WBT WBR SEL SER Lane Configurations Volume (vph) 000000 Ideal Flow (vphpl) 1900 1900 1900 1900 1900 1900 Lane Util. Factor 1.00 0.95 0.95 1.00 1.00 1.00 Frt Flt Protected Satd. Flow (prot) 0 3539 3539 0 0 0 Flt Permitted Satd. Flow (perm) 0 3539 3539 0 0 0. A 24-hour storm with a 1-in-5 year recurrence interval during a period of high groundwater and saturated soils. Peak Hour Flow (PHF). The peak flow sustained for one hour during the 24-hour, five-year return frequency storm at a time when groundwater levels are high and soils are already saturated by previous storms. Rainfall Records.
Typically, facilities are de signed for peak 15 minute flow interval 15 minute flows are accounted for through the Peak Hour Factor (PHF) Definition: Hourly Volume Peak 15 Minute Volume. 4 Typically range from 0.75-0.98 What is the highest possible value? What is the lowest possible value? Peak Hour Factor (PHF) Capacity. Or in the case of a male aged 27 with a height of 186 cm. His predicted peak flow value would be 639.948 L/min. But if he already has a measured peak flow of 568 L/min, the percentage is 88.76. 1) Nunn AJ, Gregg I. (1989) New regression equations for predicting peak expiratory flow in adults. BMJ; 298(6680):1068-70.
How does this peak flow calculator work?
This is a quick health tool that determines the estimated or predicted peak flow based on your data.
You need to select your gender and input your age and height. The former can be put in either metric (cm) or English (inches) measurement.
If you already have a peak flow determination you can input that as well to get an extra info in the result.
Based on peak flow formulas, the calculator computes the predicted value in your case and extracts the percentage the measured figure is out of the prediction. You can use the form as many times as you like varying the information or personal data.
Example calculation:
■ Let’s take for instance the case of a female aged 32 with a height of 175cm. Her estimated peak flow value would be 467.4 L/min.
■ Or in the case of a male aged 27 with a height of 186 cm. His predicted peak flow value would be 639.948 L/min. But if he already has a measured peak flow of 568 L/min, the percentage is 88.76.
References
1) Nunn AJ, Gregg I. (1989) New regression equations for predicting peak expiratory flow in adults. BMJ; 298(6680):1068-70.
2) Knudson RJ, Lebowitz MD, Holberg CJ, Burrows B. (1983) Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis; 127(6):725-34
19 Mar, 2015
Peak Hour Volume, Design Flow Rate, PHF
The following excerpts were taken from the 1994 Highway Capacity Manual, published by the Transportation Research Board.
Peak Hour and Design Hour
Capacity and other traffic analyses focus on the peak hour of traffic volume, because it represents the most critical period for operations and has the highest capacity requirements. The peak hour volume, however, is not a constant value from day to day or from season to season.
If the highest hourly volumes for a given location were listed in descending order, a large variation in the data would be observed, depending on the type of route and facility under study.
Rural and recreational routes often show a wide variation in peak-hour volumes. Several extremely high volumes occur on a few selected weekends or other peak periods, and traffic during the rest of the year is at much lower volumes, even during the peak hour. This occurs because the traffic stream consists of few daily or frequent users; the major component of traffic is generated by seasonal recreational activities and special events.
Urban routes, on the other hand, show little variation in peak-hour. . . .
The relationship between the 15-min flow rate and the full hourly volume is given by the peak hour factor, defined in Part A of this chapter (see below).
Whether the design hour was measured, established from the analysis of peaking patterns, or based on modeled demand, the peak-hour factor (PHF) is applied to determine design hour flow rates.
Peak-hour factors in urban areas generally range between 0.80 and 0.98. Lower values signify greater variability of flow within the subject hour, and higher values signify little flow variation. Peak-hour factors over 0.95 are often indicative of high traffic volumes, sometimes with capacity constraints on flow during the peak hour.
(Description of PHF from Part A, as referred to above.)
Peak rates of flow are related to hourly volumes through the use of the peak-hour factor. This factor is defined as the ratio of total hourly volume to the peak rate of flow within the hour:
PHF = Hourly volume/Peak rate of flow (within the hour)
If 15-min periods are used, the PHF may be computed as
PHF = V/(4 x V15)
Where
PHF = peak-hour factor,
V = hourly volume (vph), and
V15 = volume during the peak 15 min of the peak hour (veh/15 min).
Where the peak-hour factor is known, it may be used to convert a peak-hour volume to a peak rate of flow, as follows:
v = V/PHF (2-3)
Where
v = rate of flow for a peak 15-min period (vph),
V = peak-hour volume (vph), and
PHF = peak-hour factor.
Peak Hour 4 1 95 Resz
Equation 2-3 need not be used to estimate peak flow rates where traffic counts are available. The chosen count interval must allow the identification of the maximum 15-min flow period. The rate may then be directly computed as 4 times the maximum 15-min count.
Peak Hour 4 1 95 Mph
Many of the procedures use this conversion to allow computations to focus on the peak flow period within the peak hour.