BLOG: Power Perspectives

[#1]

Earthquakes and hurricanes pose significant threats to the operations of businesses all around the world. To ensure minimal interruption to business operations and mission critical functions during an earthquake or hurricane, generator sets should be constructed to adequately resist seismic and wind load forces.

The seismic and wind resistance capabilities of a generator set can either be qualified or certified, but how do you know which is better? Here are some basic guidelines:

Qualification may ensure that a product correctly and completely meets certain specifications, standards and requirements. It may also involve passing or successfully satisfying a specific set of tests or analyses which deem the generator set qualified to perform a special function or meet a certain requirement.

In short, qualification involves a one-time performance evaluation by test or analysis. In reality, the qualification process is just the first step toward certification, which requires a third-party review of compliance to industry standards. Certification also requires a manufacturer to have a quality control program in place to ensure that all manufactured products will meet the original qualification performance standard.

Third-party product certification by an accredited listing agency involves a review of the product qualification records and an inspection of the manufacturer's quality assurance procedures. These steps provide a higher level of confidence that the qualified product will consistently meet seismic and/or wind load requirements.

Today's International Building Codes (IBC) require seismic certification for all critical electrical equipment, including generator sets, automatic transfer switches, transformers, motor control centers, and other on-site power gear. This equipment must endure expected acceleration levels set by the U.S. Geological Survey where the equipment is installed, whether it's below ground, ground level, or on a roof top. Failure to meet these requirements could result in red-tagging, fines, penalties, a loss of certificate of occupancy and even litigation.

When it comes down to the critical functions of your business, will you specify generator sets and components that are qualified or certified to meet seismic and wind load requirements? Have you experienced a red-tagging or other set-back with your non-certified equipment?

Please share your thoughts by posting below.

[#2]

Great comments, but it should be recognized that there isn't a universal understanding of the two terms, so a designer should be looking carefully at any claims, and make sure what a supplier has done in order to justify making the claim to "certification".

[#3]

Interesting subject matter. We have done a lot of work in this field. Did Caterpillar hire an outside firm to do actual shake test on its gensets?  If so, did the test include vibration/shock isolators under the genset?

[#4]

Below are a couple of links that I hope will be helpful to those who want to understand the difference between IBC "qualification" and "certification".  The earlier comment is correct in that the Registered Design Professional needs to understand in a detailed manner "what a supplier has done" to determine if there is credibility to their claim of product qualification or certification.  To reduce potential liability, an RDP should first write a specification that will hold all suppliers accountable to provide products that are Certified in the most credible manner possible.  The most credible manner possible today is the requirement for 3rd party listing by an "Accredited Listing Agency" such as Seismic Source Interanational.  This requirement will also ensure that an owner receives what they need and expect.  Reference the following links for additional info on this subject:

http://www.cmcousa.com/docs/techbrief_ec1.pdf

http://www.cmcousa.com/docs/ibcarticle.pdf

[#5]

I will say yes and also no depending on which capacity of power you want to generate if all operationg conditions are met. Of course if it new plant it will produce the required energy it is rquired according to the manufacturer data sheet but as it is aging the the generated energy start to fall no matter the type of maintenanace you are carrying out. But general speaking if the plant is hangle by qualified personnel it must perform it required function.

Jusu Ngobeh

Electro Mechnaical Engineer

Salini

Sierra Leone

West Africa

[#6]

@ii623

I completely agree with you, that the certified vs. qualified needs to be very closely reviewed.  And this extents beyond IBC - UL and emissions certifications are two other common areas where the certification vs. qualified issue must be reviewed carefully.  And to further compound the issue, we are starting to see "compliant" coming up in discussions.  And definitely request proof of certification if it is required for your project.  It will save a number of headaches down the road. 

[#7]

@vibrodynamics

We used a third party for the IBC certification,  The actual certification process included a detailed mathmatical analysis of our packages, followed by shake table tests.  If you are interested in seeing the test, we have a short video of it on our YouTube channel (Cat IBC videos). 

And we did test with vibration isolators.  For our smaller product (approximately 600 kW and below), the isolators sit between the engine and generator are bolted together, and then is isolated from the rails.  For most of our larger generator sets (above 600 kW), the engine and generator are bolted to the base rails, and then vibration isolators were used between the base rails and the structure.