eSource 109 Ensuring Reliable Fuel in Storage for Emergency and Standby Power Systems

eSource 109 Ensuring Reliable Fuel in Storage for Emergency and Standby Power Systems

Posted 31 October 2018
Backup power systems provide an alternate source of electrical power in buildings and facilities in the event that the normal electrical power source fails. Emergency and Standby Power Systems are required to provide reliable backup to deliver electricity to critical building systems during a utility outage. Proper inspection, testing, and maintenance (ITM) are necessary for these systems to perform as intended in an emergency and unplanned power outages.

Proper ITM includes routine inspection and testing of the fuel required to power diesel generators used in Emergency and Standby Power Systems. Diesel fuel for these types of generators can be stored for an extended period of time. Diesel fuel varies in its long term storage stability. After several months the fuel can begin to age and create insoluble materials and start to oxidize depending on the storage environment and quality of the diesel fuel. Contaminants such as moisture, ingress of particulate, and microbial growth can also accumulate during long term storage.   

NFPA 110 (National Fire Protection Association) Standard for Emergency and Standby Power Systems provides a standard for testing fuel in storage for these systems. The NFPA 110 standard is cited as a mandated code referenced in several major codes and standards, including NFPA 101®, NFPA 99, the NEC®, and the International Building Code.

Though this standard provides information on testing of fuel it only references ASTM D975 (Standard Specification for Diesel Fuel Oils) with no specific guidelines as to which tests in the Standard would be applicable to fuel in long term storage for Emergency and Standby Power Systems. Testing of fuel for long term storage is not directly addressed by D975.  

Buildings that fall under Chapter 18 of NFPA 101(00) and are equipped with or house patients requiring the use of life-support systems (e.g. hospitals, nursing homes with residents on ventilators) must also meet the maintenance and testing provisions of NFPA 99, Standard for Health Care Facilities.

ALS Tribology provides a scope of testing adequate to inspection and testing of diesel fuel in long term storage for Emergency and Standby Power Systems. The scope of testing provided will monitor fuel degradation due to aging, levels of contaminants in the fuel, and the general quality of the fuel that has been provided. 

This testing should be conducted at least every six months due to the inherent storage life of diesel fuel. The advent of the increased use of biodiesel compounded with lower sulfur requirements also impacts storage stability and water tolerance in today’s diesel fuels. 

ALS Tribology provides the following recommended test package for diesel fuel in long term storage for Emergency and Standby Power Systems to ensure reliable performance when the systems are required to be available.

  • Oxidation Stability by test method ASTM D2274
  • Percent Biodiesel by test method EN14078
  • Sediment and Water by test method ASTM D2709
  • Cetane Index by test method ASTM D4737
  • Distillation by test method ASTM D86
  • Density/API Gravity by test method ASTM D287
  • Sulfur Content by test method ASTM D4294
  • Flash point by test method ASTM D93
  • Microbial growth/Bacteria by culture growth measurement
  • Appearance by test method ASTM D4176
  • Viscosity by test method ASTM D445

This testing scope will ensure and determined the reliably of the fuel stored for these systems in regards to quality of the fuel delivered, contaminants, storage stability and minimum safety limits. ALS Tribology can also provide DOT compliant sample and shipping containers to help facilitate delivery to our specialized fuel testing laboratories.

For more information email or contact your local laboratory.


Written By:

David Doyle, CLS, OMA I, OMA II
ALS Tribology


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