For Federal contracts, the contracting officer designates the size standard of the procurement by selecting the size standard for the NAICS industry that best describes the goods or services being procured. When more than one NAICS is involved in a contract, consideration is given to the function of the goods and services being purchased and the relative value and importance of each.

To bid on a Federal contract, a concern must self-certify that it is a small business under the appropriate size standard in the solicitation. The size of the concern at the time of self-certification prevails for that contract. In the 8(a) and HUBZone programs, the concern must meet the size standard for its primary industry to be admitted to the program. Then it must meet the size standard for the NAICS industry assigned to each individual contract.

If a procurement calls for two or more items with different size standards and the offeror must bid on all end items, it may qualify as a small business if it meets the common size standard for those items accounting for the greatest percentage of total contract value. If the offeror is not required to bid on all items, it may bid only on items for which it meets the size standard. To be awarded a government small business set-aside or 8(a) contract, the concern must perform at least a given percentage of the contract. This provision limits the amount of subcontracting a concern may enter into with other firms when performing these types of contracts. The provisions are as follows:

• Construction: For general and heavy construction, at least 15 percent of the cost of the contract, not including the cost of materials, must be performed by the prime contractor with its own employees. For special trade construction, such as plumbing, electrical or tile work, this requirement is 25 percent.
  
• Manufacturing: At least 50 percent of the cost of manufacturing, not including the cost of materials, must be done by the prime contractor.
  
• Services: At least 50 percent of the contract cost for personnel must be performed by the prime contractor’s own employees.
  
  

For more information, see Prime Contractor Performance Requirements (13 CFR §125.6).