MAPP gas

<h2 id="use">Use</h2>
<p>Genuine MAPP gas can be used in combination with <a href="/facts/Oxygen/acyn6o8r">oxygen</a> for heating, <a href="/facts/Soldering/fod6dLHD">soldering</a>, <a href="/facts/Brazing/JBgswMLw">brazing</a> and even <a href="/facts/Welding/6EJ62mYV">welding</a> because of its high <a href="/facts/Adiabatic_flame_temperature/l2UX9seo">flame temperature</a> of 2925 °C (5300 °F) in oxygen. Although acetylene has a higher flame temperature  (3160 °C, 5720 °F), MAPP has the advantage that it requires neither dilution nor special container fillers during transport, allowing a greater volume of fuel gas to be transported at the same given weight, and it is much safer in use.
</p><p>A MAPP/oxygen flame is not entirely appropriate for welding <a href="/facts/Steel/aN6qWo4H">steel</a>, due to the high concentration of <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a> in the flame – higher than acetylene, but lower than any of the other petroleum fuel gases. The hydrogen infuses into the molten steel and <a href="/facts/Hydrogen_embrittlement/J3JCu2Y6">renders the welds brittle</a>. For small-scale welding with MAPP this is not a serious problem, as the hydrogen escapes readily, and MAPP/oxygen can in practice be used for welding small steel parts.
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<p>MAPP/oxygen was advantageously used in underwater cutting, which requires high gas pressures (under such pressures acetylene can decompose explosively, making it dangerous to use<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>). However, underwater oxy/fuel gas cutting of any kind has been largely replaced by <a href="/facts/Thermal_lance/rvaQRHog">exothermic cutting</a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> because it cuts more quickly and safely.
</p><p>MAPP gas is also used in combustion with air for brazing and soldering, where it has a slight advantage over competing <a href="/facts/Propane/E0b23KGh">propane</a> fuel because of its higher combustion temperature of 2,020 °C (3,670 °F) in air.
</p><p>The biggest disadvantage of MAPP gas is cost; it is typically one-and-a-half times as expensive as propane at the refinery, and up to four times as expensive to the consumer. It is no longer used much in any large-scale industry – for larger scale users acetylene/oxygen is more economic than MAPP/oxygen when high flame temperatures are needed, and propane/air is more economic when big overall heating is needed.
</p><p>However, for the small-scale user a MAPP/oxygen flame is still highly desirable, having higher flame temperatures and energy densities than any flame other than acetylene/oxygen, but without the dangers and inconveniences of acetylene/oxygen. Jewellers, glassbead makers, and many others find it very useful. Plumbers, refrigeration and HVAC engineers and other tradesmen also value the high heat capacity of the MAPP/air flame; MAPP was until recently widely used, supplied in small to medium size containers.
</p><p>Blowtorches are used to brown and sear food cooked by low-temperature <a href="/facts/Sous-vide/FHmwdqbH">sous-vide</a> techniques. Myhrvold recommends in <i><a href="/facts/Modernist_Cuisine/KMaNlXMm">Modernist Cuisine: The Art and Science of Cooking</a></i> that MAPP gases should be used in preference to cheaper butane or propane as they produce higher temperatures with less risk of giving the food a gas flavour, as can happen with incompletely combusted gas.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>
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<h2 id="physical-properties">Physical properties</h2>
<p>MAPP is colorless in both liquid and gas form.  The gas has a pronounced acetylene-like or fishy odor at concentrations above 100 <a href="/facts/Parts_per_million/PozRuoLM">ppm</a>, due to the addition of substituted amines as a polymerization inhibitor. Low molecular weight alkynes have strong odors. MAPP gas is <a href="/facts/Toxic/qa96rs60">toxic</a> if inhaled at high concentrations.
</p><p>The composition of the supplied gas has varied widely, with the gases as supplied by different repackagers/resellers at any one time varying, as well as the general composition varying over time, but a typical composition for an early Dow gas might be: <a href="/facts/Methylacetylene/GJpDzkBj">methylacetylene</a> (propyne) 48%, <a href="/facts/Propadiene/AAMsUWlo">propadiene</a> 23%, <a href="/facts/Propane/E0b23KGh">propane</a> 27%. For a later Dow/Petromont gas propyne 30%, propadiene 14%, propylene 43%, propane 7%, C4H10 (<a href="/facts/Isobutane/Bd8H7rsH">isobutane</a>, <a href="/facts/Butane/InIHpYlY">butane</a>) 6% might be more typical.
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<h2 id="thermal-properties">Thermal properties</h2>
<p>MAPP has an energy content of 21000  BTU/lb (13.57 kWh/kg) while acetylene's energy content is 25000  BTU/lb (16.15 kWh/kg).<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>
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<h2 id="safety">Safety</h2>
<p>People can be exposed to MAPP gas or its substitutes in the workplace by inhaling the gas or skin/eye contact with the liquid. The <a href="/facts/Occupational_Safety_and_Health_Administration/dCGbW5Ax">Occupational Safety and Health Administration</a> (OSHA) has set the <a href="/facts/Permissible_exposure_limit/IrQeETWy">legal limit</a> for MAPP gas exposure in the workplace as 1000 ppm (1800 mg/m3) over an 8-hour workday. The <a href="/facts/National_Institute_for_Occupational_Safety_and_Health/5WjdDNMN">National Institute for Occupational Safety and Health</a> (NIOSH) has set a <a href="/facts/Recommended_exposure_limit/nexWYeNv">recommended exposure limit</a> (REL) of 1000 ppm (1800 mg/m3) over an 8-hour workday and 1250 ppm (2250 mg/m3) for short-term exposure. At levels of 3400 ppm, 10% of the lower explosive limit, MAPP gas is <a href="/facts/IDLH/ektUbSdQ">immediately dangerous to life and health</a>.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Methylacetylene-propadiene_gas/Es6N0ky7">Methylacetylene-propadiene gas</a> (MPS gas)</li>
<li><a href="/facts/Brazing/JBgswMLw">Brazing</a></li>
<li><a href="/facts/Oxy-fuel_welding/Vkucvxsy">Oxy-fuel welding</a></li>
<li><a href="/facts/Forge_welding/5YKY05fW">Forge welding</a></li>
<li><a href="/facts/Arc_Welding/SFDgoY2g">Arc Welding</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>See for example, "MAP-Pro" from BernzOmatic[1] Archived 2015-05-03 at the Wayback Machine <a href="/wiki/BernzOmatic" target="_blank">/wiki/BernzOmatic</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>https://www.todaystools.co.uk/product/9 <a href="https://www.todaystools.co.uk/product/9" target="_blank">https://www.todaystools.co.uk/product/9</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>ProTorch Map-Pro made by UltraCool – PDF <a href="https://www.princessauto.com/file/general/8899320_sds_en_01_10_31_19.pdf" target="_blank">https://www.princessauto.com/file/general/8899320_sds_en_01_10_31_19.pdf</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>https://www.toolstation.com/map-x-gas-cylinder/p71066 <a href="https://www.toolstation.com/map-x-gas-cylinder/p71066" target="_blank">https://www.toolstation.com/map-x-gas-cylinder/p71066</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>National Fire Protection Association (2010). Fire Protection Guide to Hazardous Materials (14th ed.). p. 49. https://pubchem.ncbi.nlm.nih.gov/compound/Acetylene#section=Decomposition&fullscreen=true Archived 2021-05-21 at the Wayback Machine <a href="https://pubchem.ncbi.nlm.nih.gov/compound/Acetylene#section=Decomposition&fullscreen=true" target="_blank">https://pubchem.ncbi.nlm.nih.gov/compound/Acetylene#section=Decomposition&fullscreen=true</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>"Exothermic cutting" uses the heat of burning steel wire to cut metals and even non-metals (e.g., concrete).  Typically, the wire is ignited electrically and combustion is sustained via a flow of compressed oxygen.  See:  U.S. Navy Underwater Cutting & Welding Manual, NAVSEA S0300-BB-MAN-010 (1 June 2002), Chapter 2, especially sections 2.3 (Exothermic electrodes) and 2.4 (Seeler Enterprises LU-001 Exothermic Cutting Tool (Kerie Cable)), pages 53–74 (pages 2–22 to 2–43 of original document).  Available on-line at:  http://www.maritime.org/doc/pdf/cut_weld.pdf Archived 2014-10-30 at the Wayback Machine . <a href="http://www.maritime.org/doc/pdf/cut_weld.pdf" target="_blank">http://www.maritime.org/doc/pdf/cut_weld.pdf</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Myhrvold, Nathan (2011). Modernist Cuisine: The Art and Science of Cooking. Vol. 2: Techniques and Equipment. Bellevue, Wash: Cooking Lab. p. 274. ISBN 978-0-9827610-0-7. OCLC 711381030. <a href="978-0-9827610-0-7" target="_blank">978-0-9827610-0-7</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Self, Charles R. (1982). Do Your Own Professional Welding. Blue Ridge Summit, PA: Tab Books Inc. ISBN 0-8306-0068-X. <a href="0-8306-0068-X" target="_blank">0-8306-0068-X</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>"CDC – NIOSH Pocket Guide to Chemical Hazards – Methyl acetylene-propadiene mixture". www.cdc.gov. Archived from the original on 2022-01-25. Retrieved 2015-11-20. <a href="https://www.cdc.gov/niosh/npg/npgd0393.html" target="_blank">https://www.cdc.gov/niosh/npg/npgd0393.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
</ol>

MAPP gas open-in-new

MAPP gas