Industrial Lubricants

Topics of this section include:



The real world of the 1990's places heavy demands on equipment. We expect equipment to operate between -50C and 150C without production loss or increased maintenance costs. Lubricants can be considered a vital component of every machine. Notwithstanding extreme temperatures, many machines are heavily loaded, and operate at higher speeds with smaller reservoirs and longer lubricating intervals.

Proper lubrication is vital in any operation and is determined from the "Four R's".

The Original Equipment Manufacturer (OEM) together with your Petro-Canada Lubricants Representative or Technical Services Advisor can assist you in determining the "Four Rights" for your equipment or machinery.


Viscosity Classification of Industrial Oils

It had been the practice in North America for many years to define the viscosity of industrial lubricating oils in Saybolt Universal Seconds (SUS) at reference temperatures of 100 F and 210 F.

However, there is now a world-wide acceptance of the International Organization for Standardization's (ISO) proposal 3448-1975 (E) to establish viscosity measurements in centistokes (cSt) at 40 C and 100 C temperatures.


Advantages of ISO Viscosity Grades

International acceptance benefits customers, manufacturers and marketers. The lubricant grade recommended by the equipment manufacturer is the same as the number in the product name. Conversion from one viscosity measurement to another is virtually eliminated. The number in the product name for most products represents the viscosity of an industrial oil.

Not involved in this new measurement system are all automotive crankcase and gear oils which continue to be designated by the Society of Automotive Engineers (SAE) viscosity classifications. The table below shows the kinematic viscosity limits for each ISO Viscosity Grade. Each viscosity grade is 50% higher in viscosity than the preceding viscosity grade. These limits are set at a 10 percent tolerance level above and below the mid-point of a grade. Any product with a viscosity outside these tolerance levels is not a recognized ISO Viscosity Grade.


ISO-Viscosity System for Industrial Fluid Lubricants

Kinematic Viscosity Limits  
ISO Viscosity Grade Mid Point cSt @ 40 C Minimum Maximum
cSt S.U.S. cSt S.U.S.
2 2.2 1.98 32.0 2.42 34.0
3 3.2 2.88 35.5 3.52 37.5
5 4.6 4.14 39.5 5.06 42.5
7 6.8 6.12 46.0 7.48 50.5
10 10 9.00 55.5 11.0 62.5
15 15 13.5 71.5 16.5 83.5
22 22 19.8 97.0 24.2 116
32 32 28.8 136 35.2 165
46 46 41.4 193 50.6 235
68 68 61.2 284 74.8 347
100 100 90.0 417 110 510
150 150 135 625 165 764
220 220 198 917 242 1121
320 320 288 1334 352 1631
460 460 414 1918 506 2344
680 680 612 2835 748 3465
1000 1000 900 4169 1100 5095
1500 1500 1350 6253 1650 7643

AGMA Numbers

The American Gear Manufacturers Association (AGMA) has set up a numbering system to define gear oil viscosities required for various speed reducer types and applications. These AGMA Lubricant Numbers are normally stamped on the manufacturer's metal name plate. ISO Viscosity Grade numbers and AGMA numbers can be compared as shown in the table below.

AGMA # R & O ISO VG Grade Viscosity Range cSt @ 40 C
- 1 46 41.4 - 50.6
2 EP 2 68 61 - 75
3 EP 3 100 90 - 110
4 EP 4 150 135 - 165
5 EP 5 220 198 - 242
6 EP 6 320 288 - 352
7 EP 7A Comp 460 414 - 506
8 EP 8 Comp 680 612 - 748
8A EP 8A Comp 1000 900 - 1100

AGMA # EP requirements are met by Ultima EP mild gear oils of proper viscosity. R&O requirements are met with Premium R&O and Harmony AW. The compounded grades designated "COMP" are met with the Senate grades, which contain additional lubricity additives. Automotive gear oils for hypoid gears are designated by SAE for viscosity grades and API for quality levels. These oils may be used in many speed reducers but oils designed to meet AGMA requirements cannot be used in automotive differentials and transmissions.


Viscosity Comparisons

Viscosities designated by various societies or organizations may be compared as shown in the table opposite.

This is strictly a viscosity comparison and in no circumstance should it be construed as a quality level comparison. To summarize -

ISO VG is viscosity measurement in centistokes (cSt) at 40 C.
AGMA viscosity grades as designated by the American Gear Manufacturers Association.
SAE Society of Automotive Engineers viscosity measurement for automotive engine and gear oils e.g. SAE 30, SAE 90, etc.
Saybolt These units are in S.U.S. and were used by various refiners/blenders to specify viscosity at 100 F or 210 F.

How to use the chart: For instance, if a manufacturer requests a non-detergent SAE 30 oil for a piece of equipment, go to the SAE viscosity column and follow across horizontally to the left to read an ISO VG of 100. Non-detergent suggests that it is not a typical engine oil, as all engine oils contain detergents. In order to recommend the correct product, the end-use application should be determined. For example,


Viscosity equivalents chart


Handy Conversion Tables

Viscosity Guide Table of Limits

Maximum Viscosities
(Normally At Start-Up)
22,000 Probably maximum pouring viscosity.
11,000 Probably maximum for splash or bath lubrication.
8,600 Barely pumpable by gear or piston pump ­ too heavy to be serviceable.
2,200 Upper limit for an automatic oil lubricator.
2,200 Upper limit for circulation system (good practice).
2,200 Upper limit for an oil constituent of a grease for dispensing.
1,000 Ring or rolling element bearings.
860 Hydraulic Vane Pumps @ start-up temperature ­ to prevent cavitation and wear.
860 Fuel oil for good pumpability and atomizing.
220 Oil mist generators without heat at minimum operating temperature.
220 Hydraulic-piston pump ­ start-up temperature ­ to prevent wear.
54 Hydraulic Systems at operating fluid temperature.

Minimum Viscosities
(At Operating Temperature)
33 F or gear lubrication.
30 For a gear pump.
21 Spherical roller bearings.
13 Other rolling element bearings.
13 Hydraulic systems to prevent excessive pump wear and slippage.
13 Plain bearings.
4 Minimum viscosity to support a dynamic load.


Optimum Viscosities

The optimum viscosity is the ideal allowable at the operating temperature.


25 Hydraulic systems
30 Plain Bearings
40 Spur & Helical Gears (e.g. ISO-VG 150 @ 60 C)
75 Worm Gears (e.g. 460 @ 75 C)


Lubricants Handling and Storage

Petro-Canada's lubricating oils and greases are the result of considerable research work and, after careful manufacture and delivery, are as good for their intended use as we can make them. However, during storage it is important to guard against contamination, which can drastically reduce the performance and life of a lubricant. Numerous studies have shown that both water and dirt can lessen the life of bearings and other components. Preventing contamination during storage has a direct pay-back in terms of optimum lubricant performance, longer lubricant life and reduced maintenance costs.

Inside Storage

Lubricants preferably should be stored inside. However, even then there are certain precautions that should be followed:

Outside Storage

If outside storage is unavoidable, then the following precautions should be followed:


Lubricating oils and greases are a relatively harmless class of material. Nevertheless, care should be taken to avoid skin contact and inhalation of oil mists during use. Petro-Canada provides Material Safety Data Sheets (MSDS) on all of its products and these are available from your Sales Representative or our Technical Services Department.

Some general guidelines for personnel handling lubricating oils and greases follow: