Formerly known as the British Standards Institution, the firm took the decision to hire an agency to improve promotion of its global, commercial business interests.
The brief also includes promotion of the Kitemark's centenary next year.
The appointment of BPGR reunites Chime with BSI. Chime's Keith McDowall Associates, since rebranded as the political communications arm of BPGR, previously held a PA brief with the firm but was axed in 2001 as part of a cost- cutting drive.
This is the first external agency hire since then and the first firm to be hired to provide global corporate and consumer PR support. The decision to take on agency support was made by MD Stevan Breeze during the summer and follows a restructure to create five divisions.
These are British Standards (which has a Department of Trade and Industry grant and includes the Kitemark), Management Systems, Business information, Product Services and Inspectorate.
Breeze said: 'A lot of people seem to think we are all civil servants but that's not the case, we are a growing global business and that message needs to get out.'
He added it was just the British Standards arm that has a government grant and that the other divisions are solely commercially driven.
BPGR won the account following a three-way pitch. The account team is headed by director David Hill, who reports to head of corporate affairs Alick Whitfield.
BSI Group has a turnover of £235m and employs 5,000 staff globally.
Earlier this year it acquired the US certification arm of professional services giant KPMG, making it the largest certification company in North America.