High-Piled Storage Terms

When discussing your project, the terminology is critical.  Please read below to familiarize yourself with some common high-piled storage terminology.

Being on the same page is critical to project success.  These terms will help you.

Most of the confusion an end user will face when signing a warehouse lease results from the terminology involved.  The reason for this problem is that often times terms are used interchangeably, although they have distinct meanings in different contexts.  For instance, aisle spacing is a big one.  The rack consultant has one meaning for aisle spacing, the fire code consultant has one  meaning for aisle spacing, and then the building department has yet another meaning for aisle spacing.  Not all aisles are created equal, so it is important to understand the difference between them.

  • Aisle Spacing: The width of an aisle as it relates to commodity separation for sprinkler protection, storage truck travel aisles, and required egress aisles.  Each has a minimum requirement, and changing one may affect another.
  • Apparatus Roadway: A road that provides fire apparatus access from a fire station to a facility, building or portion thereof. This is a general term inclusive of all other terms such as fire lane, public street, private street, parking lot lane and access roadway.
  • Apparatus Roadway Certification: The above defined apparatus access roadway must be certified by a Professional Engineer to be capable of supporting the imposed load of fire apparatus weighing at least 90,000 pounds.
  • Building Department Permits: Permits required by the City shall be obtained from the fire code official. Permit fees, if any, shall be paid prior to issuance of the permit. Issued permits shall be kept on the premises designated therein at all times and shall be readily available for inspection by the fire code official. Most projects require a permit. Any alteration, repair, remodel, renovation, or new construction in both residential and commercial buildings requires permits. Any work done to repair, replace, alter or install mechanical, electrical and plumbing equipment also requires a permit, but if no plans are involved these certain trade permits may be obtained online by the licensee.
  • Certificate of Compliance: A type of Occupancy Certificate issued for a process or addition, certifying that the work or process meets specific standards for such. An example would be a certificate issued for a new paint booth operation added to an existing (F) Occupancy. If an occupancy has an existing approved certificate, then the addition of high piled combustible storage will result in a certificate of compliance once plans review and inspections are approved.
  • Certificate of Occupancy: A certificate issued by the Building Department that identifies a specific business and lists the occupancy(s) approved for that specific address/location. It also identifies the code of record assigned to the Occupancy(s).
  • Code of Record: The Construction Codes adopted by municipalities and used for the purpose of plans development and review based upon the time of its construction. Certain features of a building may be reviewed under its original, older building code upon request and approval from both the fire marshal’s office and building department.
  • Commodity Classifications: Commodities shall be classified as Class I, II, III, IV or high hazard. Class I and II Commodities are non-combustible materials with various combustible packaging. Class III and IV Commodities are combustible materials with limited amounts of plastic materials. High Hazard Commodities are materials, such as Group A Plastics, which present special fire hazards beyond that found in Class I-IV Commodities.
  • Control Mode Sprinkler System: A type of sprinkler used to protect a commodity utilizing a density of water flow through an orifice (gpm/ft2) over a specified design area (ft2) intended to control the fire until the fire department arrives.
  • Fire Department Connection: An important component required for sprinkler and standpipe systems. When a sprinkler system activates, the fire department connects hose lines from a pumper truck to the fire department connection. This connection allows the fire department to supplement the fire protection system in the event of a fire.
  • Fire Fighter Access Door: Man doors provided for firefighting purposes. High Piled Storage Facilities are required to provide firefighter access doors for every 100 lineal feet of wall adjacent to a high piled storage area facing an apparatus access road. The doors must be accessible without a ladder and must allow egress from the interior of the building and entrance from the exterior of the building.  
  • Fire Marshal Permits: Permits regulated by the Houston Fire Marshal’s Office. These include key box, high piled combustible storage, hazardous material, hot works, and other permits regulated by the fire marshal on a renewal basis. They come with a fee paid yearly.
  • Egress Lighting: A combination of lighting equipment to provide one-foot candle of illumination along walking surface of the common path of egress of a building under emergency power outage conditions.
  • ESFR Sprinkler System: Early Suppression Fast-Response (ESFR) sprinkler. A sprinkler system utilizing larger orifices and quick response to deliver large amounts of water over the fire intended to suppress the fire prior to fire department arrival. It is designed based on the orifice size of the sprinkler and its operating pressure.
  • FM4430: This is the FM Global sponsored test that certified automatic, drop out smoke and heat vents.  It is the most commonly used vent in Houston, but it is no longer compliant for use in newer code buildings.  Also, these vents are not allowed for use with ESFR sprinkler systems.  This standard dictates the temperature at which the acrylic dome shall drop out of the frame to vent smoke and heat from the building.
  • Hazardous Enterprise Permit: A certificate issued by the Planning Department approving a property for Hazardous Materials use. It is attached to the property and is transferrable.
  • Hazardous Materials Inventory Statement: Abbreviated as HMIS, this document identifies all hazardous materials to be used or stored at a particular occupancy and details the individual hazards for each product as well as the amounts to be used or stored.
  • High Piled Combustible Storage: Storage of combustible materials in closely packed piles or combustible materials on pallets, in racks or on shelves where the top of storage is greater than 12 feet in height. When required by the fire code official, high- piled combustible storage also includes certain high-hazard commodities, such as rubber tires, Group A plastics, flammable liquids, idle pallets and similar commodities, where the top of storage is greater than 6 feet in height.
  • High Piled Combustible Storage Permit: A Fire Marshal regulated permit issued to a specific business, and renewed yearly, for high piled storage facilities. The initial purchase of this permit triggers an inspection from the Fire Marshal’s High Piled Storage Team, and subsequent plans development and review for the proposed high piled storage arrangement are required to validate the permit. These inspections will result in either a certificate of occupancy or a certificate of compliance.
  • High Piled Combustible Storage Permit Approval: When all prerequisites have been met, including plans review and inspections, a Fire Inspector will code the High Piled Permit as APPROVED.
  • Maximum Allowable Quantities (MAQ’s): The amount of any particular Hazardous Material that can be stored in an (S) Occupancy.
  • Mixed Storage of Mixed Commodities: A situation where groups of moderate hazard (Class I-IV) and/or groups of high hazard (Group A Plastics and higher) are stored together in the same high piled storage area. In these cases, protection must be provided for the highest hazard commodity.
  • Notice of Violation: A written document prepared by a Fire Inspector following an inspection. It outlines code violations and gives a time frame for their correction.
  • Occupancy: The classification of a habitable facility based on use designations as prescribed in the Building Code.
  • Permit Office: The Houston Permitting Center (HPC) combines the majority of the City of Houston's permitting and licensing into one location.
  • Sprinkler Technical Report: Also known as a sprinkler evaluation, is a report prepared by a licensed sprinkler designer detailing the systems capability to protect an existing storage arrangement.
  • Standpipe: A system of piping with connection devices at both ends that acts to extend the reach of fire apparatus to portions of a structure that lack apparatus roadways.
  • UL-793: This is the UL sponsored fire test that certified automatically operated roof vents for smoke and heat removal. The vents covered by this requirement are operated manually or automatically in the event of fire to remove smoke and heat from the building. Automatic operation does not depend on electrical power or other energy sources that may be interrupted during a fire, but rather depends upon operation of a heat responsive device or on the action of a plastic cover shrinking and falling from place due to fire exposure, or the like. These vents are not intended for use as general purpose building ventilation devices. The currently adopted Building and Fire Codes only allow for UL-793 rated smoke and heat vents.  Future codes will allow for the FM Global standard to be used as well.


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