Camp chillers and fan-coil loops at Oman rig sites need a glycol based heat transfer fluid even though the water never freezes, because inhibited glycol protects the pipework from corrosion and slows microbial growth. This glycol based heat transfer fluid HVAC guide explains which glycol to choose, how strong to mix it, which water to use and how to test it on site. Oman Chem supplies Heat Transfer Glycol Liquid, Heat Transfer Fluids SH and MPG Antifreeze Heat Transfer Liquid from Barka Industrial Area, Sultanate of Oman.
Glycol based heat transfer fluid HVAC basics for rig camps
A glycol heat transfer fluid is ethylene glycol (MEG) or propylene glycol (MPG, monopropylene glycol) mixed with water and an inhibitor package. It circulates in closed-loop heating, cooling and chilled water systems. At a camp that means the containerised chiller outside, the fan-coil units in each cabin and the loops that serve the kitchen cold rooms.
Glycol heat transfer fluids typically operate from about -51°C to 121°C (-60°F to 250°F), and heating and cooling systems usually run below about 82°C (180°F). Camp HVAC sits well inside that range. Glycol carries less heat than plain water, so expect somewhat lower cooling capacity, higher pumping power and a larger temperature difference across the chiller. Ask your chiller supplier to confirm the unit is rated for the glycol percentage you plan to use.
Why use glycol in Oman's heat when water never freezes
Most glycol guides are written for cold countries and treat freeze protection as the only reason to add it. At a camp where summer temperatures reach 40 to 50°C, the reasons are different.
- Corrosion control. Industrially inhibited glycol typically contains 4 to 6% inhibitors to protect the metals in the loop. Industrial HVAC glycol fluids are commonly tested to the ASTM D1384 corrosion test, typically less than 0.5 mils per year penetration on system metals: copper, solder, brass, steel, cast iron and cast aluminium.
- pH buffering. A 50% solution of inhibited propylene glycol typically sits at pH 9.0 to 10.5, and its reserve alkalinity holds the pH there as the fluid ages.
- Biostatic action. Loops below 25% glycol are prone to microbial growth and glycol breakdown. A loop at 25% or more resists the slime and bacterial fouling that warm water encourages.
- Cold nights and low-temperature loops. Winter nights in the interior desert can turn cold, and process chillers and cold-store loops run well below ambient. Choose a freeze point at least 3°C (5°F) below the lowest expected ambient or operating temperature.
Mobile chillers that move between PDO concessions, Duqm and Nizwa also stand idle between contracts. An inhibited fill goes on protecting the steel while the unit stands, whereas plain water leaves it open to rust.
MEG vs MPG for camps with kitchens and accommodation
Ethylene glycol is the more common choice for HVAC because it has lower viscosity and transfers heat better, but it is moderately toxic. Propylene glycol is much less toxic and has about twice the viscosity of ethylene glycol, which raises pumping cost and reduces heat transfer somewhat.
At a rig camp the kitchen, the potable water tanks and the staff cabins often sit close to the HVAC plant. Propylene glycol fluids are the choice wherever incidental contact with people, food or drinking water is possible, and their ingredients are generally recognised as safe (GRAS) by the US FDA. For cabins and kitchen cold rooms we recommend our MPG Antifreeze Heat Transfer Liquid. For an isolated process or equipment loop, ask us about Heat Transfer Glycol Liquid or Heat Transfer Fluids SH, and we will confirm the glycol base of each grade on the quote.
Typical specs of inhibited heat transfer glycol
The figures below are typical for an industrially inhibited propylene glycol concentrate of this product class. They are not the measured specification of our product.
| Item | Detail |
|---|---|
| Part numbers | RXSOL-81-1586-210 (Heat Transfer Glycol Liquid), RXSOL-81-1586-211 (Heat Transfer Fluids SH), RXSOL-81-1586-230 (MPG Antifreeze Heat Transfer Liquid) |
| Application | Closed-loop chilled water, heating and process cooling systems |
| Typical composition | About 95.5% glycol by weight and about 4.5% inhibitors and water; inhibitors often phosphate-based |
| Specific gravity | 1.050 to 1.060 at 60°F (15.6°C), typical |
| pH of 50% solution | 9.0 to 10.5, typical |
| Reserve alkalinity | About 10 ml minimum, typical |
| Appearance | Colourless to clear, or dyed for leak detection |
| Typical working dilution | 25% to 65% glycol by volume, balance purified water |
Dilution and water quality in Oman
Typical working dilution is 25% to 65% glycol by volume, balance purified water. Solutions below 25 to 30% may not give adequate corrosion protection. In Oman freeze risk rarely sets the strength, so the inhibitor and biostatic minimum usually does. Typical freeze points by volume are:
- Propylene glycol: 30% about -13°C (8°F), 40% about -22°C (-7°F), 50% about -33°C (-28°F), 60% about -51°C (-60°F).
- Ethylene glycol: 30% about -16°C (3°F), 40% about -25°C (-13°F), 50% about -37°C (-35°F).
The dilution water decides how long the fill lasts. Usual limits are chloride under 25 ppm, sulphate under 25 ppm, and calcium and magnesium hardness each under 50 ppm. Distilled, deionised or RO water is recommended.
Brackish borehole water at interior camps is unlikely to meet those limits, and trucked water can vary from load to load. Test desalinated supply before you use it. If you cannot get RO or deionised water on site, ask us for a pre-diluted fluid instead of concentrate. That takes both the mixing step and the water risk away from the camp crew.
Filling, testing, storage and disposal
Before filling, clean new or lightly corroded systems with a 1 to 2% trisodium phosphate solution, then flush. Do not mix glycol types or brands, because incompatible inhibitor packages can separate and clog filters, strainers and pump suctions. If the loop held a different product, drain and flush it fully first.
Avoid automatic water make-up, which dilutes the glycol without anyone noticing. On camp units we suggest isolating the make-up line and topping up by hand with fluid premixed at the same strength. Do not top up with automotive antifreeze from the workshop: its high silicate inhibitor levels can foul heat exchangers and cause pump seal failures. Uninhibited glycol is no better, since an uninhibited ethylene glycol solution is about 4.5 times more corrosive to carbon steel than plain water.
A refractometer is the practical field check for glycol percentage. Have your maintenance crew log the refractometer reading and pH on a fixed schedule, and send samples for periodic lab analysis of reserve alkalinity, inhibitor level and contamination. Warning signs of degradation are pH falling below about 8, a sharp or septic odour, rising iron and copper, and microbial growth.
Store drums out of direct sunlight or under cover. Long sun exposure has been reported to change the colour and properties of the fluid, and drums left on an open laydown yard in the interior get the full summer sun, so keep them in a shaded store. The flash and fire points of glycols are above the boiling point of water, so water blends of 20% or more glycol present little fire hazard in storage or handling.
Never drain glycol heat transfer fluid to sewers or onto open ground. A system contaminated with any ethylene glycol must be handled as toxic, and larger volumes need a licensed waste contractor. Follow your contractor's HSE waste procedure and Oman's environmental requirements for collection.
Where to buy glycol heat transfer fluid in Muscat and Oman
Oman Chem (Muscat & Barka for Business Trading) supplies glycol heat transfer fluids from Barka Industrial Area, Sultanate of Oman. Tell us about your loop and we will advise on the right grade. Call +968 77333599, message us on WhatsApp, or browse the drilling fluids and oilfield chemicals range.
The same Heat Transfer Glycol Liquid is also listed for Muscat building and facility orders on our Muscat Chemical product page, and for Sohar port and Batinah plant deliveries on our Sohar Chemical product page.
To request a quote, send us the loop volume, the chiller model and whether the loop serves cabins or kitchens on WhatsApp at +968 77333599. We will reply with the right grade for your loop.
Frequently asked questions
Why use glycol in a hot climate where water never freezes?
In Oman the main reasons are corrosion control, pH buffering and slowing microbial growth. Inhibited glycol carries an inhibitor package that protects steel, copper and aluminium, and loops below 25% glycol are prone to microbial growth and glycol breakdown. It also protects low-temperature process loops and units exposed to cold desert nights.
What percentage of glycol should be in a closed-loop HVAC system?
Typical working dilution is 25% to 65% glycol by volume, balance purified water. Solutions below 25 to 30% may not give adequate corrosion protection. Choose a freeze point at least 3°C (5°F) below the lowest expected ambient or operating temperature, and do not go below 25% for inhibitor and biostatic protection.
Should I use ethylene glycol or propylene glycol at a rig camp?
Ethylene glycol transfers heat better and has lower viscosity, but it is moderately toxic. Propylene glycol is much less toxic and is the choice wherever incidental contact with people, food or drinking water is possible. At camps where kitchens, potable water and cabins sit near the HVAC plant, we recommend the propylene (MPG) grade.
Can I use automotive antifreeze in an HVAC chiller?
No. Automotive antifreeze is unsuitable for HVAC and industrial loops because its high silicate inhibitor levels can foul heat exchangers and cause pump seal failures. Use an industrially inhibited glycol made for closed-loop HVAC, and do not mix glycol types or brands in the same loop.
How do you test glycol concentration in an HVAC system?
A refractometer is the practical field check for glycol percentage. Check pH as well, and send samples for periodic lab analysis of reserve alkalinity, inhibitor level and contamination. Warning signs of degradation are pH falling below about 8, a sharp or septic odour, rising iron and copper, and microbial growth.