Birmingham_gauge
Birmingham gauge
Wire gauge system used in medicine
The Birmingham gauge[1] is a wire gauge system, and is also used to specify thickness or diameter of hypodermic needles and tube products.
Birmingham gauge is also known as the Stubs Iron Wire Gauge or Birmingham Wire Gauge. It is not the same as, though similar to, the Stubs Steel Wire Gauge.
Birmingham gauge is often simply termed Gauge, with the abbreviation G.[2] However, this should not be confused with French gauge.
The gauge starts at the lowest gauge number of 5Ø or 00000, corresponding to the largest size of 0.500 inches (12.7 mm), and runs to the highest gauge number of 36, corresponding to the smallest size of 0.004 inches (0.10 mm). Size steps between gauges range from 0.001 inches (0.025 mm) between high gauge numbers to 0.046 inches (1.2 mm) between the two lowest gauge numbers and do not correspond to a particular mathematical pattern, although for the most part the steps get smaller with increasing gauge number.[3] Concerning wire and fine tubing, the gauge number is used to specify the outside diameter of the product, whereas for larger mechanical tubing the gauge number specifies the wall thickness independent of the overall size of the tube.
In medicine, the Birmingham gauge specifies the outside diameter of hypodermic needles, catheters, cannulae and suture wires. It was originally developed in early 19th-century England for use in wire manufacture, and began appearing in a medical setting in the early 20th century.
Another common needle gauge system is the French catheter scale.
Needle wire gauge was derived from the Stubs Iron Wire Gauge.
Hypodermic needles are available in a wide variety of outer diameters described by gauge numbers. Smaller gauge numbers indicate larger outer diameters.[4] Inner diameter depends on both gauge and wall thickness. The following chart shows nominal inner diameter and wall thickness for regular-wall needles.[4][5] Thin-wall needles (not shown) have identical outer diameters but larger inner diameters for a given gauge.
Gauge, G |
Nominal outer diameter | Nominal inner diameter[lower-alpha 1] | Nominal wall thickness[lower-alpha 1] | ISO 6009 color[6] | ||||||
---|---|---|---|---|---|---|---|---|---|---|
(inch) | (mm) | (inch) | (mm) | (inch) | (mm) | |||||
7 | 0.180 ± 0.001 | 4.572 ± 0.025 | 0.150 ± 0.003 | 3.810 ± 0.076 | 0.015 ± 0.001 | 0.381 ± 0.025 | (undefined) | |||
8 | 0.165 ± 0.001 | 4.191 ± 0.025 | 0.135 ± 0.003 | 3.429 ± 0.076 | 0.015 ± 0.001 | 0.381 ± 0.025 | (undefined) | |||
9 | 0.148 ± 0.001 | 3.759 ± 0.025 | 0.118 ± 0.003 | 2.997 ± 0.076 | 0.015 ± 0.001 | 0.381 ± 0.025 | (undefined) | |||
10 | 0.134 ± 0.001 | 3.404 ± 0.025 | 0.106 ± 0.003 | 2.692 ± 0.076 | 0.014 ± 0.001 | 0.356 ± 0.025 | Olive brown | |||
11 | 0.120 ± 0.001 | 3.048 ± 0.025 | 0.094 ± 0.003 | 2.388 ± 0.076 | 0.013 ± 0.001 | 0.330 ± 0.025 | Green-yellow | |||
12 | 0.109 ± 0.001 | 2.769 ± 0.025 | 0.085 ± 0.003 | 2.159 ± 0.076 | 0.012 ± 0.001 | 0.305 ± 0.025 | Pale blue | |||
13 | 0.095 ± 0.001 | 2.413 ± 0.025 | 0.071 ± 0.003 | 1.803 ± 0.076 | 0.012 ± 0.001 | 0.305 ± 0.025 | Purple | |||
14 | 0.083 ± 0.001 | 2.108 ± 0.025 | 0.063 ± 0.003 | 1.600 ± 0.076 | 0.010 ± 0.001 | 0.254 ± 0.025 | Pale green | |||
15 | 0.0720 ± 0.0005 | 1.829 ± 0.013 | 0.0540 ± 0.0015 | 1.372 ± 0.038 | 0.0090 ± 0.0005 | 0.229 ± 0.013 | Blue-grey | |||
16 | 0.0650 ± 0.0005 | 1.651 ± 0.013 | 0.0470 ± 0.0015 | 1.194 ± 0.038 | 0.0090 ± 0.0005 | 0.229 ± 0.013 | White | |||
17 | 0.0580 ± 0.0005 | 1.473 ± 0.013 | 0.0420 ± 0.0015 | 1.067 ± 0.038 | 0.0080 ± 0.0005 | 0.203 ± 0.013 | Red-violet | |||
18 | 0.0500 ± 0.0005 | 1.270 ± 0.013 | 0.0330 ± 0.0015 | 0.838 ± 0.038 | 0.0085 ± 0.0005 | 0.216 ± 0.013 | Pink | |||
19 | 0.0420 ± 0.0005 | 1.067 ± 0.013 | 0.0270 ± 0.0015 | 0.686 ± 0.038 | 0.0075 ± 0.0005 | 0.191 ± 0.013 | Cream | |||
20 | 0.03575 ± 0.00025 | 0.9081 ± 0.0064 | 0.02375 ± 0.00075 | 0.603 ± 0.019 | 0.00600 ± 0.00025 | 0.1524 ± 0.0064 | Yellow | |||
21 | 0.03225 ± 0.00025 | 0.8192 ± 0.0064 | 0.02025 ± 0.00075 | 0.514 ± 0.019 | 0.00600 ± 0.00025 | 0.1524 ± 0.0064 | Deep green | |||
22 | 0.02825 ± 0.00025 | 0.7176 ± 0.0064 | 0.01625 ± 0.00075 | 0.413 ± 0.019 | 0.00600 ± 0.00025 | 0.1524 ± 0.0064 | Black | |||
22s | 0.02825 ± 0.00025 | 0.7176 ± 0.0064 | 0.00600 ± 0.00075 | 0.152 ± 0.019 | 0.01110 ± 0.00025 | 0.2826 ± 0.0064 | (undefined) | |||
23 | 0.02525 ± 0.00025 | 0.6414 ± 0.0064 | 0.01325 ± 0.00075 | 0.337 ± 0.019 | 0.00600 ± 0.00025 | 0.1524 ± 0.0064 | Deep blue | |||
24 | 0.02225 ± 0.00025 | 0.5652 ± 0.0064 | 0.01225 ± 0.00075 | 0.311 ± 0.019 | 0.00500 ± 0.00025 | 0.1270 ± 0.0064 | Medium purple | |||
25 | 0.02025 ± 0.00025 | 0.5144 ± 0.0064 | 0.01025 ± 0.00075 | 0.260 ± 0.019 | 0.00500 ± 0.00025 | 0.1270 ± 0.0064 | Orange | |||
26 | 0.01825 ± 0.00025 | 0.4636 ± 0.0064 | 0.01025 ± 0.00075 | 0.260 ± 0.019 | 0.00400 ± 0.00025 | 0.1016 ± 0.0064 | Brown | |||
26s | 0.01865 ± 0.00025 | 0.4737 ± 0.0064 | 0.00500 ± 0.00075 | 0.127 ± 0.019 | 0.00680 ± 0.00025 | 0.1734 ± 0.0064 | (undefined) | |||
27 | 0.01625 ± 0.00025 | 0.4128 ± 0.0064 | 0.00825 ± 0.00075 | 0.210 ± 0.019 | 0.00400 ± 0.00025 | 0.1016 ± 0.0064 | Medium grey | |||
28 | 0.01425 ± 0.00025 | 0.3620 ± 0.0064 | 0.00725 ± 0.00075 | 0.184 ± 0.019 | 0.00350 ± 0.00025 | 0.0889 ± 0.0064 | Blue-green | |||
29 | 0.01325 ± 0.00025 | 0.3366 ± 0.0064 | 0.00725 ± 0.00075 | 0.184 ± 0.019 | 0.00300 ± 0.00025 | 0.0762 ± 0.0064 | Red | |||
30 | 0.01225 ± 0.00025 | 0.3112 ± 0.0064 | 0.00625 ± 0.00075 | 0.159 ± 0.019 | 0.00300 ± 0.00025 | 0.0762 ± 0.0064 | Yellow | |||
31 | 0.01025 ± 0.00025 | 0.2604 ± 0.0064 | 0.00525 ± 0.00075 | 0.133 ± 0.019 | 0.00250 ± 0.00025 | 0.0635 ± 0.0064 | White | |||
32 | 0.00925 ± 0.00025 | 0.2350 ± 0.0064 | 0.00425 ± 0.00075 | 0.108 ± 0.019 | 0.00250 ± 0.00025 | 0.0635 ± 0.0064 | Deep green | |||
33 | 0.00825 ± 0.00025 | 0.2096 ± 0.0064 | 0.00425 ± 0.00075 | 0.108 ± 0.019 | 0.00200 ± 0.00025 | 0.0508 ± 0.0064 | Black | |||
34 | 0.00725 ± 0.00025 | 0.1842 ± 0.0064 | 0.00325 ± 0.00075 | 0.0826 ± 0.019 | 0.00200 ± 0.00025 | 0.0508 ± 0.0064 | Orange | |||
Rapid blood transfusion through 23G or smaller needles can cause hemolysis (rupturing of red blood cells).[7]
This includes peripheral venous catheters. The gauge compared to outer diameter is the same as for needles, but the color coding is different.
- Wire gauge, including other systems
- French gauge, mainly for catheters
- American Wire Gauge
- "'French', 'gauge' and millimeters". University of California, San Francisco. Archived from the original on 2017-08-18. Retrieved 2018-02-03.
- Machinery's Handbook 27. New York, NY: Industrial Press, Inc. 2004. p. 2520.
- "Syringe Needle Gauge Chart". Sigma Aldrich. Retrieved 20 March 2012.
- "Hypodermic Needle Gauge Chart". Medical Tube Technology, Inc. Archived from the original on 10 October 2004. Retrieved 20 March 2012.
- Page 110 in: Edward Doyle (2007). Pediatric Anesthesia. OUP Oxford. ISBN 978-0-19-920279-9.
- ISO 9626: Stainless steel needle tubing for the manufacture of medical devices, 1st ed. Geneva: International Organization for Standardization, 1991: 1–2.
- ISO 9626: Stainless steel needle tubing for the manufacture of medical devices, Amendment 1. Geneva: International Organization for Standardization, 2001: 1–2.
- Wonsik Ahn; Jae-Hyon Bahk; Young-Jin Lim (2002). "The "Gauge" System for the Medical Use". Anesthesia & Analgesia. 95 (4): 1125. doi:10.1097/00000539-200210000-00076. PMID 12351319.
- Iserson KV (1987). "The origins of the gauge system for medical equipment". J Emerg Med. 5 (1): 45–8. doi:10.1016/0736-4679(87)90009-6. PMID 3295010.
- Sheet Metal Gauge Size Data – Engineers Edge