If a Pressure Gauge Is Reading 15.2 Bar the Psi Equivalent Would Be

CHARACTERISTICS OF COMPRESSED AIR

R. Keith Mobley , in Fluid Power Dynamics, 2000

Guess Pressure level

Gauge pressure is the virtually oft used method of measuring pneumatic pressure. It is the relative force per unit area of the compressed air within a system. Gauge pressure level can be either positive or negative, depending upon whether its level is above or beneath the atmospheric pressure reference. Atmospheric pressure level serves as the reference level for the about significant types of pressure measurements. For case, if we inflate a tire to xxx psi, an ordinary tire-force per unit area gauge will express this pressure as the value in excess of atmospheric force per unit area, or 30 psig ("m" indicates gauge force per unit area). This reading shows the numerical value of the difference betwixt atmospheric pressure and the air force per unit area in the tire.

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Basic Flow Theory

Westward. Brian Rowe DSc, FIMechE , in Hydrostatic, Aerostatic and Hybrid Bearing Design, 2012

Force per unit area Ratio and the Blueprint Status

Gauge pressure ratio P_r /P_s is given by equations such equally (two.25) and (2.26). More generally, values are given by blueprint charts such as those in Capacity vii and 8 Chapter 7 Chapter 8 for variations with load and displacement. Pressure ratio varies with film thickness and applied load. If one value of the film thickness is denoted the design condition—that is, h_o —the particular value of pressure ratio is termed β, which is the ratio P_ro /P_southward , where P_ro is the value of pressure P_r when h  = h_o . For liquid hydrostatic bearings, ambient pressure is commonly taken as aught and all pressures are relative to ambient conditions so that approximate pressure ratio is

$\beta =\frac{P_{ro}}{P_{\mathrm{southward}}}\text{Liquid}$

The usefulness of designating a blueprint condition is that it allows load, flow, and stiffness variations to be explored for different values of β. A value β  =   0.v allows loads to be increased or reduced equally in either sense.

Traditionally, the symbol for gauge pressure level ratio K_go is employed for gas:

$K_{mo}=\frac{p_{ro}-p_a}{p_s-p_a}\text{Gas}$

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Data charts and tables

Peter D. Osborn BScEng (Hons), C Eng, FIEE Engineering Consultant , in Handbook of Energy Data and Calculations, 1985

A35 Steam pipe capacities (kg/s)

A35.1. Gauge pressure (kPa) and velocity (m/s)

Gauge pressure level (kPa)	Velocity (g/s)	External diameter and nominal bore of pipage (mm)
		21.3	26.ix	33.7	46.4	48.iii	60.3	76.i	88.ix	114.3	139.7	168
		xv.0	20.0	25.0	32.0	40.0	50.0	65.0	lxxx.0	100	125	150
40	fifteen	0.0017	0.0037	0.0064	0.0100	0.014	0.027	0.040	0.058	0.ten	0.eighteen	0.25
	25	0.0028	0.0066	0.011	0.017	0.025	0.044	0.072	0.ten	0.18	0.26	0.40
	forty	0.0046	0.010	0.017	0.028	0.039	0.073	0.xi	0.16	0.28	0.46	0.63
70	15	0.0019	0.0043	0.0068	0.011	0.016	0.030	0.045	0.068	0.12	0.19	0.28
	25	0.0033	0.0072	0.012	0.019	0.027	0.049	0.077	0.12	0.19	0.31	0.43
	40	0.0048	0.010	0.019	0.029	0.046	0.081	0.12	0.17	0.xxx	0.47	0.66
100	15	0.0023	0.0052	0.0085	0.013	0.020	0.035	0.056	0.082	0.14	0.22	0.33
	25	0.0037	0.0095	0.014	0.023	0.032	0.059	0.093	0.13	0.23	0.36	0.51
	twoscore	0.0059	0.012	0.023	0.035	0.054	0.ten	0.15	0.21	0.37	0.57	0.81
200	15	0.0031	0.0066	0.012	0.019	0.027	0.050	0.077	0.eleven	0.20	0.31	0.43
	25	0.0052	0.012	0.019	0.031	0.044	0.081	0.12	0.eighteen	0.33	0.48	0.69
	40	0.0081	0.017	0.031	0.048	0.075	0.13	0.20	0.28	0.52	0.80	1.fourteen
300	15	0.0043	0.010	0.016	0.025	0.035	0.067	0.eleven	0.15	0.25	0.41	0.56
	25	0.0070	0.015	0.027	0.041	0.061	0.12	0.17	0.25	0.43	0.68	0.94
	forty	0.011	0.024	0.043	0.068	0.098	0.16	0.28	0.twoscore	0.seventy	1.11	i.63
400	15	0.0050	0.011	0.019	0.030	0.042	0.077	0.12	0.17	0.32	0.46	0.67
	25	0.0080	0.018	0.031	0.049	0.074	0.12	0.twenty	0.thirty	0.54	0.80	1.sixteen
	forty	0.013	0.032	0.054	0.081	0.13	0.22	0.34	0.l	0.86	1.36	i.94
500	xv	0.0060	0.014	0.024	0.036	0.051	0.ten	0.14	0.21	0.37	0.57	0.80
	25	0.010	0.022	0.038	0.059	0.082	0.fifteen	0.25	0.35	0.61	0.98	1.42
	40	0.016	0.037	0.064	0.096	0.14	0.25	0.39	0.56	1.00	1.57	2.24
600	15	0.0070	0.016	0.029	0.042	0.061	0.12	0.17	0.25	0.43	0.69	0.93
	25	0.012	0.026	0.044	0.069	0.10	0.18	0.29	0.41	0.69	1.xvi	one.68
	twoscore	0.019	0.043	0.074	0.11	0.16	0.28	0.44	0.62	1.15	1.78	ii.55
700	15	0.0077	0.016	0.030	0.045	0.071	0.12	0.nineteen	0.26	0.fifty	0.76	1.09
	25	0.013	0.031	0.052	0.079	0.12	0.21	0.33	0.48	0.83	1.32	1.88
	40	0.021	0.048	0.083	0.12	0.xix	0.33	0.51	0.69	1.26	2.07	ii.98
800	15	0.0087	0.019	0.034	0.051	0.077	0.13	0.22	0.thirty	0.54	0.82	i.23
	25	0.015	0.033	0.055	0.087	0.13	0.22	0.34	0.51	0.89	1.43	2.03
	40	0.023	0.052	0.089	0.fourteen	0.20	0.37	0.56	0.85	i.twoscore	2.23	3.41
1000	15	0.011	0.024	0.040	0.064	0.096	0.xvi	0.26	0.38	0.64	1.03	one.51
	25	0.018	0.039	0.070	0.11	0.15	0.27	0.42	0.sixty	1.05	1.72	ii.46
	forty	0.028	0.059	0.xi	0.17	0.25	0.45	0.69	1.00	i.76	2.lxx	3.93
1400	15	0.014	0.033	0.050	0.084	0.thirteen	0.22	0.35	0.51	0.88	1.43	2.02
	25	0.023	0.053	0.090	0.14	0.21	0.38	0.57	0.85	1.42	ii.32	iii.43
	40	0.035	0.083	0.15	0.22	0.33	0.60	0.94	1.thirty	2.33	3.57	five.11

A35.two. Steam pipage capacities (kg/due south) Showing relationship to force per unit area drop gene F (see B17.iv.iii)

External diameter and nominal bore of pipe (mm)
F	21.3	26.9	33.7	46.four	48.iii	60.3	76.1	88.nine	114.three	139.seven	168	191	219	241	273	324
	15.0	20.0	25.0	32.0	40.0	50.0	65.0	80.0	100	125	150	175	200	225	250	300
0.000 16						0.009	0.015	0.025	0.055	0.100	0.166	0.247	0.35	0.49	0.65	1.07
0.000 20					0.0045	0.010	0.017	0.029	0.063	0.113	0.184	0.279	0.40	0.55	0.73	1.xviii
0.000 25				0.0030	0.0050	0.011	0.019	0.031	0.069	0.124	0.200	0.303	0.43	0.60	0.79	1.28
0.000 xxx				0.0033	0.0054	0.012	0.021	0.034	0.075	0.134	0.216	0.327	0.47	0.65	0.86	ane.38
0.000 35			0.0019	0.0035	0.0057	0.012	0.024	0.036	0.080	0.144	0.232	0.35	0.50	0.69	0.92	ane.48
0.000 45		0.0010	0.0022	0.0040	0.0065	0.014	0.026	0.042	0.093	0.164	0.264	0.37	0.54	0.74	1.04	1.68
0.000 55		0.0011	0.0025	0.0045	0.0073	0.016	0.029	0.047	0.104	0.184	0.296	0.43	0.61	0.84	one.17	1.88
0.000 65		0.0012	0.0028	0.0049	0.0081	0.017	0.031	0.051	0.114	0.204	0.33	0.48	0.69	0.95	1.29	2.08
0.000 75		0.0014	0.0031	0.0054	0.0088	0.019	0.034	0.056	0.124	0.224	0.36	0.53	0.76	1.06	one.41	2.28
0.000 85		0.0015	0.0033	0.0059	0.0096	0.021	0.038	0.061	0.135	0.244	0.39	0.58	0.83	1.17	i.54	two.48
0.001 00	0.0005	0.0016	0.0036	0.0065	0.0106	0.023	0.041	0.068	0.150	0.269	0.44	0.66	0.94	i.31	1.73	2.79
0.001 25	0.0006	0.0018	0.0039	0.0072	0.0118	0.025	0.046	0.076	0.167	0.30	0.49	0.76	1.04	one.45	1.92	3.1
0.001 50	0.0007	0.0020	0.0042	0.0079	0.0131	0.028	0.050	0.083	0.184	0.34	0.54	0.85	ane.15	1.lx	2.xi	iii.iv
0.001 75	0.0007	0.0022	0.0046	0.0086	0.014	0.030	0.055	0.091	0.201	0.37	0.59	0.95	1.26	1.74	ii.30	3.8
0.002 00	0.0008	0.0024	0.0051	0.0093	0.016	0.033	0.060	0.099	0.218	0.twoscore	0.64	one.05	1.36	1.88	2.49	4.1
0.002 5	0.0009	0.0027	0.0056	0.010	0.017	0.037	0.067	0.110	0.241	0.45	0.71	i.11	1.52	2.10	2.fourscore	4.6
0.003 0	0.0010	0.0030	0.0062	0.011	0.019	0.041	0.074	0.121	0.265	0.49	0.78	one.eighteen	one.68	2.31	3.1	5.0
0.004 0	0.0011	0.0035	0.0073	0.013	0.022	0.048	0.087	0.143	0.31	0.57	0.92	1.40	ii.00	2.75	3.7	half-dozen.0
0.005 0	0.0013	0.0039	0.0082	0.015	0.025	0.054	0.098	0.160	0.35	0.64	one.03	1.59	2.27	3.1	iv.one	6.8
0.006 0	0.0014	0.0044	0.010	0.017	0.027	0.060	0.109	0.180	0.39	0.71	1.15	1.74	2.52	three.4	4.6	7.5
0.008 0	0.0017	0.0051	0.011	0.019	0.032	0.070	0.126	0.208	0.46	0.83	1.35	two.04	two.9	4.0	5.3	8.7
0.010 0	0.0019	0.0058	0.012	0.022	0.036	0.079	0.143	0.235	0.52	0.92	1.52	2.31	three.3	iv.5	6.0	ix.8
0.012 5	0.0021	0.0065	0.013	0.024	0.040	0.088	0.160	0.258	0.58	1.03	1.70	2.56	3.seven	5.0	6.7	10.9
0.015 0	0.0023	0.0071	0.015	0.027	0.044	0.096	0.177	0.290	0.63	1.14	one.87	2.82	4.0	five.five	vii.3	12.0
0.017 v	0.0025	0.0077	0.016	0.030	0.048	0.105	0.194	0.31	0.69	1.25	two.05	3.07	four.4	6.0	8.ane	xiii.0
0.020	0.0027	0.0084	0.017	0.032	0.052	0.114	0.210	0.34	0.75	i.36	2.22	3.33	four.8	6.5	8.vii	14.0
0.025	0.0030	0.0094	0.019	0.036	0.059	0.127	0.232	0.38	0.83	one.51	2.47	3.71	5.3	7.3	9.vii	15.7
0.030	0.0033	0.0104	0.021	0.040	0.065	0.140	0.255	0.42	0.92	one.66	two.72	four.09	five.9	eight.0	10.half dozen	17.iv
0.040	0.0039	0.0123	0.025	0.047	0.078	0.167	0.xxx	0.50	i.09	1.97	three.22	4.84	vii.0	ix.6	12.half dozen	twenty.8
0.050	0.0045	0.0138	0.028	0.053	0.087	0.188	0.34	0.56	1.22	ii.23	iii.62	five.four	7.9	10.ix	14.three	23.7
0.060	0.0049	0.0148	0.031	0.058	0.095	0.208	0.38	0.62	i.35	2.45	3.98	five.9	8.7	12.0	15.9
0.080	0.0057	0.0174	0.037	0.068	0.112	0.242	0.44	0.72	ane.58	2.84	4.62	6.8	10.1
0.100	0.0065	0.0196	0.041	0.077	0.126	0.272	0.50	0.82	i.78	3.20	5.24	seven.six
0.12	0.0071	0.0214	0.045	0.085	0.139	0.300	0.55	0.90	one.95	3.52	five.78
0.xv	0.0079	0.0241	0.050	0.094	0.154	0.334	0.61	1.00	2.18
0.20	0.0093	0.0285	0.060	0.111	0.183	0.396	0.72	one.17	2.58
0.25	0.0104	0.0316	0.067	0.124	0.204	0.440	0.lxxx	1.29
0.30	0.0114	0.0348	0.074	0.137	0.225	0.484	0.88	1.41
0.35	0.0125	0.0379	0.081	0.150	0.246	0.528	0.95
0.40	0.0135	0.0411	0.088	0.163	0.267	0.571	one.03
0.45	0.0144	0.0439	0.093	0.174	0.285	0.607
0.50	0.0153	0.0466	0.098	0.185	0.302	0.643
0.60	0.0169	0.0518	0.109	0.204	0.333
0.70	0.0183	0.0562	0.118	0.222
0.80	0.0196	0.0603	0.126	0.238
0.90	0.0208	0.0641	0.135

A36. CIBS Psychrometric chart

(Reproduced by permission of the Chartered Institution of Building Services. Pads of charts for record purposes can exist obtained from CIBS, Delta House, 222 Balham High Road, London SW12 9BS)

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The Yates Bearing

Due west. Brian Rowe DSc, FIMechE , in Hydrostatic, Aerostatic and Hybrid Begetting Design, 2012

Concentric Judge Recess Pressures

The concentric approximate pressure ratio at entry into the journal bearing is termed β ₁  = K _go1  =P ₁/P _{due south} and in the thrust bearings is β _ii  = 1000 _becomeii  = P ₂/P _southward , where P ₂ is the gauge pressure at entry to the thrust pad and P _s is the supply approximate pressure level. Splitting the force per unit area differences every bit from supply force per unit area P _south downwards to β _ane P _s and then downwards to β ₂ P _{due south} allows bearing pressures to vary upwardly and downwards equally in both the radial and axial directions. An equal divide makes pressure level ratios β ₁  =   0.67 and β ₂  =   0.33. A slightly larger maximum radial load support can exist obtained past reducing β ₂ down to say 0.2. A general guide for β ₁ may be obtained by illustration with a conventional hydrostatic bearing where the recommended pressure ratio is 0.5. For a Yates begetting it is recommended that

(11.1) ${\beta }_1=(1+{\beta }_2)/2\text{Pressure}\text{ratios}$

The design procedure that follows assumes that this recommendation is followed. Thus, if the axial pressure level ratio β _ii  =   0.two, the journal pressure level ratio is β _i  =   0.six. Acceptable thrust begetting load back up tin usually be obtained with these values. The combination β _ane  =   0.6 and β ₂  =   0.2 will oftentimes, therefore, be adopted.

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Instrumentation and control

In The Efficient Use of Energy (2nd Edition), 1982

Strain-approximate Pressure Transducers.

Strain-gauge pressure transducers incorporate a number of desirable features. The form of construction enables a compact assembly to be engineered to perform accurately and reliably in farthermost environmental atmospheric condition and with highly corrosive fluids.

The output takes the form of varying d.c. voltage that does not depend on brush contacts (as with Potentiometric pick-offs), and the signal voltage is sufficiently high to exist compatible with most data acquisition systems.

Various methods are used to construct strain-judge pressure transducers just all are based on ane of ii principles, namely 'bonded' or 'unbonded'. The bonded form is the simplest form of construction because it involves the attachment of a fine wire or piezo-electric strain guess by direct adhesion to the pressure diaphragm. The unbonded blazon gauge is possibly the more versatile form of construction. It comprises a fine tungsten–platinum resistive wire of some 5 μm diameter wound effectually sapphire posts which are mounted on a star-spring structure. The wire filaments are cemented with high-temperature epoxy resin to ensure maximum stability of the sensing element in harsh vibrational environments. A wide range of sensitivities is obtained with this type of pressure transducer by varying the diaphragm thickness and force-summing expanse, star-bound thickness and strain-estimate wire resistance.

1 manufacturer has produced transducers roofing pressure level ranges from every bit low every bit 0–xv kPa to 0–66 MPa and temperatures between –160°C and +325°C. Numerous variants are available, specifically designed to be resistant to nuclear radiation or corrosive liquids, with accuracies (including combined linearity and hysteresis errors) of ±0.five% of total range output. Two sensing arrangements are used; one utilizes a rhombic structure described beneath, the other a 'flat' sensing device, both being designed with a view to minimizing the effects of vibration and acceleration by making the mass of the sensitive element as small-scale as possible in keeping with the spring tension.

A schematic diagram of an unbonded strain-estimate pressure transducer element is shown in Figures 31 and 32 .

Effigy 31. Unbonded strain-gauge pressure transducer

Figure 32. Span circuit configuration.

Courtesy Bong and Howell Ltd, Electronics and Instruments Division

The center of the transducer comprises the strain judge which is subjected to strain practical in the windings by ways of forces that are in turn applied in a controlled fashion by the pressure force being measured. A typical transducer associates is shown sectioned in Figure 33 . The force per unit area causes displacement of the diaphragm. A force rod connected to the centre of the diaphragm transmits the force (proportional to the applied pressure) to the sensing chemical element. Transducers of this type have been adult to meet requirements for medical, aerospace, nuclear and industrial environments.

Effigy 33. Unbonded strain-gauge force per unit area transducer.

Courtesy Bell and Howell Ltd, Electronics and Instruments Sectionalisation

A transducer of particular interest for industrial applications is a bonded strain-gauge instrument designed to measure a low differential pressure in the presence of a high line pressure level up to 20 MPa. The unit of measurement converts differential pressures over the range 0–250 cm to 0–750 cm of h2o into a proportional electrical output of 0 to 15 mV d.c.

Positive overpressure protection is provided by mechanical stops, enabling the transducer to withstand overpressure of 20 MPa applied to either side without departure in specifications. One such design is claimed to withstand 24 MPa without diaphragm rupture. An electrical network mounted in a junction box provides compensation for changes in zero pressure output and full-scale pressure output due to changes in temperature. The unit has provision for external shunt scale.

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ASME B31.3: Pressure Blueprint

Clifford Matthews , in A Quick Guide to API 570 Certified Pipework Inspector Syllabus, 2009

12.4 Pipe wall thickness equations

The API 570 syllabus requires candidates to be able to calculate pipage wall thickness (t _min)and MAWP values. These are mainly of use in assessing whether corroded pipework tin can exist safely endorsed for use until the side by side planned inspection rather than for detailed 'design' adding, as such.

The equations are found in B31.3 section 304; these cover straight pipes under internal pressure level. The main ones (sometimes referred to every bit the Boardman equations) are, from section 304.one.two:

(known as equation 3(a)) $\mathrm{Wall}\mathrm{thickness}\left(\mathit{t}\right)=\frac{\mathit{PD}}{2\left(\mathit{SE}+\mathit{PY}\right)}$

and

(known every bit equation iii(b)) $\mathit{t}=\frac{\mathit{P}\left(\mathit{d}+2\mathit{c}\right)}{2\left[\mathit{Sew}-\mathit{P}\left(\mathrm{i}-\mathit{Y}\right)\right]}$

where

P = internal gauge pressure

D = pipe exterior bore

S = material allowable stress from B31.3 table A-ane

E = a longitudinal 'quality cistron' from B31.3 tabular array A-1A or A-1B

Y = a coefficient from B31.3 table 304.one.1

W = a weld gene from B31.3 para. 302.3.v(e)

d = pipe inside diameter

c = sum of 'mechanical allowances'

Note the predominance of 'factors' in these equations. While they no dubiousness take a justified place in the lawmaking, many of them (mainly those in equation three(b)) take limited utilise in many inspection-related calculations and practice non announced regularly in API examination questions. Notation how the gene W (only recently added to the code in 2004) only appears in equation 3(b).

Exam questions (open-book) on this topic consist mainly of simple substitution of numbers into these formulae. Variations on the theme include:

•

Using a transposed formula to detect P (MAWP) when t is given.

•

Calculating MAWP at a future fourth dimension when the current (t) has been reduced past a given 'corrosion allowance'.

•

Calculating the safe time to the next inspection on the basis of the 'one-half-life' principle of API 570.

One interesting point to note is how ASME and API codes take slightly unlike approaches to wall thickness/MAWP calculations. While B31.3 quotes the Boardman equations 3 (a) and 3(b), API 570/574 prefer the simplified 'Barlow' equation as follows:

$\mathit{t}=\frac{\mathit{PD}}{2\mathit{SE}}\left(\mathrm{see}\mathrm{API}574\mathrm{section}11\right)$

In practice, the ASME and API approaches requite answers that are adequately close, every bit long as the design temperature of the pipe is not also loftier (when the Y-factor of B31.3 table 304.one.i will have more of an effect).

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Pressure level

P.D. Davis BSc CPhys MIstP MIPSM , ... G.N.C. Kenny BSc (Hons) Md FRCA , in Basic Physics and Measurement in Anaesthesia (Fourth Edition), 1995

Approximate AND ABSOLUTE PRESSURES

A full oxygen cylinder has a estimate pressure of 137 bar. When the cylinder is empty the estimate records 0 bar simply, unless a vacuum pump has been used, the cylinder still contains oxygen at the ambience atmospheric pressure level, and the true or absolute pressure in the empty cylinder is almost 1 bar ( Fig. 1.6). In most cases, anaesthetists can ignore atmospheric force per unit area and use gauges that record the approximate pressure above or below existing atmospheric force per unit area. Thus, ventilator and gas-cylinder pressures, arterial blood pressure and venous pressure readings are all gauge pressures.

To avert confusion the term 'accented pressure' is used when the full pressure including atmospheric pressure is required. The accented force per unit area for the empty oxygen cylinder is about 1 bar; so for a full cylinder, if the guess force per unit area is 137 bar the absolute force per unit area is 138 bar.

$\text{A}\text{b}\text{s}\text{o}\text{l}\text{u}\text{t}\text{e}\text{p}\text{r}\text{e}\text{s}\text{s}\text{u}\text{r}\text{e}=\text{G}\text{a}\text{u}\text{g}\text{east}\text{p}\text{r}\text{e}\text{s}\text{s}\text{u}\text{r}\text{eastward}+\text{A}\text{t}\text{grand}\text{o}\text{southward}\text{p}\text{h}\text{east}\text{r}\text{i}\text{c}\text{p}\text{r}\text{eastward}\text{south}\text{s}\text{u}\text{r}\text{e}$

Atmospheric pressure at the surface of the earth is due to the gravitational force on the air molecules in a higher place, the actual force per unit area depending on the density of air over the indicate concerned which, in turn, depends on altitude and weather conditions.

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PNEUMATIC MECHANICAL INSTRUMENTATION

JOHN South. Page , in Computer's Piping Man-Hr Manual (Fifth Edition), 1999

PNEUMATIC Pressure level INSTRUMENTS

Local Mounted

Homo HOURS EACH

Item	Man Hours Each
PT gauge pressure transmitter, pneumatic. Foxboro Model: 11 GM. Range: spans from 10–2,000 psi with maximum range of iii,000 psi inside limits of range sheathing, maximum overrange iv,000 psi. Materials: 316 SS. Procedure Connexion: ¼" or ½" NPT female. Output Signal: 3–15 psi. Mounting: Bracket for 2″ pipe. With air filter-regulator set and mounting bracket.	7.half dozen
PT absolute pressure transmitter, pneumatic. Foxboro Model: 11 AH. Range Capsule: xx–200 psi, adjustable span, maximum overrange 350 psi. Body Cloth: 316 SS. Process Connection: ½" NPT female. Output Signal: 3–fifteen psi. Mounting: Bracket for 2″ pipe. With air filter-regulator set and mounting subclass.	7.6
PTI pressure indicating transmitter, pneumatic indicating. FoxboroModel: 45P. Case: Rectangular. Range: 0–10 to 0–2,000 psi. Calibration: Eccentric, vi-?" length. Output Signal: 3–15 psi. Pressure Chemical element: Cu-Ni-Mn, Diaphragm. With air filter-regulator set and mounting yoke.	5.1
PR pressure level recorder directly connected. Foxboro Model: 40PR. Instance: Rectangular. Mounting: Yoke, Chart Drive: Electric, 115 volts, threescore Hz., 24-hour. Range: 0–10 to 0–ii,000 psi. Pen: One. Force per unit area Element: Cu-Ni-Mn, diaphragm. With mounting yoke.	15.ii
PC pressure level controller, pneumatic, direct continued. Foxboro Model: 43AP-FA4. Command Role: Proportional plus reset. Prop. Band: 4–400%. Reset Time: 0.5–25 minutes. Range: 0–x to 0–two,000 psi. Element: Cu-Ni-Mn, Diaphragm. Calibration: Eccentric. Relay Action: Reversible. Set Point Knob: Internal. Output Gauge: 0–30 psi. Mounting: Bracket for 2″ piping. With air filter-regulator set and mounting subclass.	15.2

Above man hours include checking out of storage, calibrating, hauling to erection site, installing, testing, and final checkout.

Human hours do not include connections to process and air signal lines. See piping accounts for these charges.

Man hours do not include wiring for recorder electrical charge bulldoze. See Electrical Man Hour Manual for this charge.

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Reservoir fluid properties

Abdus Satter , Ghulam M. Iqbal , in Reservoir Technology, 2016

Estimation of reservoir pressure

Reservoir pressure is estimated by reservoir depth, and modify of pressure with depth.

Reservoir pressure is unremarkably expressed as gauge pressure and accented pressure. The unit of gauge pressure is psi ^−one. Absolute pressure = judge force per unit area + atmospheric force per unit area (usually 14.7 psi). The unit of absolute pressure is psia. It can be shown that the pressure gradient of fresh h2o is 0.433 psi⁻¹, considering its density (62.4 lb-m/ft.ⁱⁱⁱ), units of area (ane ft.² = 144 in.²), dispatch due to gravity (32.ii ft./south²), and lb-g to lb-f conversion factor.

(4.26) $(62.4\text{lb-chiliad}/\text{ft}{\text{.}}^{\mathrm{iii}})\times (1\text{ft}{\text{.}}^{\mathrm{two}}/144\text{in}{\text{.}}^{\mathrm{ii}})\times (32.2\text{ft.}/{\text{southward}}^2)/(32.2\text{lb-m}\text{ft.}/\text{lb-f}{\text{south}}^2)=0.433\text{psi}/\text{ft.}$

The pressure gradient implies that the fresh h2o (sp. gr. = 1.0) would exert a force per unit area of 0.433 ft.^−one of depth in the reservoir. Formation water, however, is heavier than fresh water as it contains dissolved solids. The specific gravity of germination is greater than ane.0. Hence, information technology exerts more pressure level per foot of depth in the reservoir. The pressure slope of formation water is calculated as:

(4.27) $\text{Change}\text{of}\text{pressure}\text{of}\text{formation}\text{water}\text{with}\text{depth}=0.433{\gamma }_{\text{westward}}\text{psi}/\text{ft.}$

where γ _w = specific gravity of formation water, ratio.

When reservoir depth and the specific gravity of germination water or connate water are known, the reservoir pressure can exist calculated as follows:

(4.28) $p=0.433{\gamma }_{\text{westward}}D+\mathrm{xiv.seven}\text{psia}$

where D = reservoir depth, feet.

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Leaks

Trevor Kletz , in What Went Wrong? (Fifth Edition), 2009

34.5 Leaks from Screwed Fittings

During a pressure test at a gauge pressure level of about 350 bar (5,000 psi), a 20-mm (¾-in.) screwed thermowell was diddled out at loftier speed (about xc mi/h) and seriously injured a man who was looking for possible leaks. The report [ 7] does non say whether the failure was due to corrosion, damaged threads, failure to fully appoint the threads, or incompatibility of the two threads, merely all of these take acquired other failures of screwed joints (see Section 28.4.two). Many companies do not permit the employ of screwed joints except for depression-pressure lines handling nonhazardous liquids (hot h2o is considered hazardous) and for small diameter lines, such every bit those leading to instruments, and so only after the outset isolation valve.

Pressure level tests are carried out to confirm that the equipment can withstand the examination pressure and, therefore, we should assume that failure is possible and continue everyone out of the way. If we were sure the equipment would not fail, we would not need to test it. Leaks can be detected by testing at the operating force per unit area.

A screwed nipple and valve blew off an oil line operating at 350°C (660°F). An oil mist 30 m (100 ft) deep covered most of the unit and was sucked into the control room past the ventilation fan. The operators managed to shut downwards the plant before the oil mist caught fire well-nigh 15 minutes afterward.

Many people practice not realize that mists of flammable liquids can burn or explode at temperatures well below the flash point of the vapor. The droplets acquit like particles of dust, but in that location is often some vapor present as well, and thus these explosions may exist more than powerful than dust ones.

The nipple that failed was installed during structure to aid pressure testing and was non shown on any drawing. If the operating team had known information technology was there, they would have replaced it with a welded plug. Afterward, they drew up a listing of other weak spots in piping systems to exist identified and modified if this was practical, and, if not, they inspected the weak points regularly. The following is based on their list [8].

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