What is Annular Space?

This post provided by Sharron Halpert at Halpert Life Safety Consulting

ANNULAR SPACE- This is a term used only in a discussion of through penetration firestop not in rated joints. It is basically the gap. More specifically it is the distance from the inside edge of the opening to the outside edge of the penetrating item. It is actually a critical and often overlooked part of a firestop assembly.
When measuring the annular space, sometimes it gives a “nominal” measurement. If the detail says nominal ½”, then the tested and listed detail expects the field condition to have a pipe that is centered in the opening. That can happen, and it snows in Las Vegas…sometimes. More often the annular space will offer parameters defined by a minimum and maximum annular space. If the annular space lists 0” to 1” this means that the penetrating item does not need to be centered in the hole. It also means that its okay if the penetrating item makes contact on one side.
This does NOT mean that when an electrician runs a 1” conduit, they can use a 1” hole saw. Some contractors see the 0”-1” and think that the pipe can squeeze into the opening and the firestop contractor can firestop the application. This happens all the time, but that doesn’t make it right. It only makes it common.
When the opening is just barely big enough to allow the pipe through, this creates a condition known as CONTINUAL POINT CONTACT. Another time this can occur is when a 6” sleeve is run for a 4” pipe that will have 1” insulation on it. There is enough room to get everything through the sleeve, but there will not be enough room to install the firestop detail that should have been submitted.
There are very few tested and listed systems that allow CONTINUAL point of contact for a bare metal pipe, let alone for a combustible penetration such as insulation or even plastic. This gap is critical to the proper performance of the firestop assembly. If the tested and listed detail calls for 0”-1” then it assumes there will be some space into which the sealant can be installed. For a typical 1-hour gypsum wall the required sealant thickness will likely be 5/8”. If there isn’t at least ¼” gap, then the sealant depth cannot be achieved. This is critical to the performance of the firestop installation.  We will go into this in depth, but for now we are not finished with the discussion about annular space. How do you measure it?
If there is a square duct in a square hole, measuring the annular space is pretty simple. If it is a round pipe in a round hole, its simple again. What about when you have a round pipe in a square hole? Do you measure to the longest distance, which would be to the corner or do you measure from the edge? According to UL, the measurements should be made to the edge, so basically at a 90-degree angle from the edge of the opening to the side of the pipe.
That covers annular space pretty well for now, but there is more to consider. If you have any questions feel free to reach out to us and we are happy to help if we can. Next up we will talk about the hose stream test. This will help clarify why the annular space is such an important element to verify during a firestop inspection. You will know how a continual point contact installation will likely fail and much, much more. Thank you for taking the time to learn more about firestop. 

4 Components of a Service Delivery Evaluation

def., the simultaneous occurrence of events or circumstances

As communities grow and housing developments expand, they can outgrow the local municipalities ability to provide efficient and effective emergency response, fire protection, and life safety services. To address this issue NFPA 1, Chapter 15, Fire Department Service Delivery Concurrency Evaluation provides guidance and authority to the AHJ to ensure that an adequate level of service is maintained.  

This section identifies several expectations that must be met by both, the developer, and the fire department. Only those developments that increase the fire department service area population or building square footage by more than 1% can require a fire department concurrency evaluation.  This suggests that the department should have some form of community risk assessment (which would include an analysis of total building stock and square footage) available.  Otherwise, the 1% increase may not be able to be proved.

The concurrency evaluation can be conducted by those individuals that the AHJ determines to be qualified.  These qualifications may come through experience, education, or other special knowledge. There are four components that the evaluation must include.

Component 1. The current level of fire protection, life safety, and fire prevention services must be clearly stated and demonstrated.

Component 2. The predicted post-development fire protection, life safety, and fire prevention service impacts must be shown. Any additional staffing, facilities, and resources required should be clearly stated and provided for in the evaluation.

Component 3. The post-development level of service may fall below current level of service and be accepted if their is a mitigation plan in place.  All recommendations and mitigation plans are to be included in the evaluation.

Component 4.  The funding sources and methods to pay the costs of the mitigation recommendations is to be clearly shown.

The concurrency evaluation is conducted at the expense of the developer. The development cannot proceed until the required concurrency evaluation has been conducted and approved by the AHJ.

Multiple tools, resources, and skills are required by the evaluator. A community risk assessment or community risk reduction plan is important for providing a current picture of a communities population, properties, and fire protection and life safety services and programs. Using a blend of data and business analytics tools, accurate post-development predictions and service impacts can be forecast. The most current editions of NFPA 1710, 1720, and 1730 outline minimum services to provide and the staffing levels required to provide those services.

How to Analyze Fire Protection Problems (Part 2)

An essential quality of any management consultant is the ability to solve problems in a structured, hypothesis-driven manner.  The 4-step process used by McKinsey & Co. to solve management problems can be applied to analyze and find solutions to physical fire protection system and component design and problems.

Step 1. Frame the problem. McKinsey employs the acronym ‘MECE’ to form a framework and structure for problem-solving.  MECE stands for ‘mutually exclusive, collectively exhaustive’.  To properly frame a problem it must be separated into distinct, overlapping issues, while making sure that no issue relevant to the problem has been overlooked. Structure and frameworks help to ensure that no part of the problem is missed. Management consultants apply a logic tree to visually depict this framework, however, using a framework  common to our industry can be more productive.  A common framework within the fire service would be the ICS (incident command system) structure.
For fire protection problem solving these components may look like this:

INCIDENT COMMAND - Issue or problem statement; design criteria/need
OPERATIONS - How is this system supposed to function? How does the system actually function?
PLANNING - How is the system designed? Is the design appropriate for the hazard?
LOGISTICS - What system components or resources are required for effective operation?
FINANCE - What costs are involved in this system installation, testing, or maintenance?

Utilizing a problem-solving framework a hypothesis can then be formed. The hypothesis can provide a problem-solving roadmap that will lead to the asking the right questions. The authors of, The McKinsey Mind state that it is “more efficient to analyze the facts of a problem with the intent of proving or disproving a hypothesis than to analyze those facts one by one to determine which answer they will eventually provide”.  An initial hypotheses can be formed by drawing conclusions based on the limited facts known. Brainstorming with a team can be helpful for developing and testing a hypothesis and forming new ideas.  The goal should be to get to the root of the problem, not just address issue symptoms.  

Step 2. Design the analyses. From the initial problem-solving framework determine what factors most affect the problem, and focus on those. Take a “big picture” view and resist the onslaught of tunnel vision.  Ensure the focus area is moving in the right direction, toward the goal of problem resolution. Do not over-analyze.  Do just enough to prove (or disprove) the hypothesis, then move on.

Step 3. Gather the data.  To this point we have been brainstorming and creating hypothesis based on “general information” and the problem framework.  When a logical analysis has been designed, data to support that must be collected.  There are 3 primary methods of data gathering:
  1. Research - reports, documentation, outliers, and best practices
  2. Interviews - pulling out information from those most intimate with the problem or need
  3. Knowledge management (KM) - reaching out to experts, networks, and groups

Step 4. Interpret the results. This should be a culmination of the hard work that was done in the previous three steps. This is the time to sift through and organize all the data that has been collected. If the problem has been properly framed, an analyses based on factors most affecting the problem has been designed, and thorough data has been gathered the problem solution will often present itself.

This is Part 2 of a 6 part series collectively titled, McKinsey Method for Fire Protection Solutions. As you read keep in mind that these systems and processes can be applied to  fire protection organization and leadership, and to physical fire protection systems and components.

Protecting Cable Sleeve Penetrations

An often overlooked, but critical component of building and occupant fire safety is fire barriers, and fire-resistance-rated construction. Beyond reasons of code requirements, fire-rated barriers are an essential component of a buildings life safety system.  These barriers work in conjunction with the sprinkler system to ensure that a fire cannot grow beyond the sprinklers capacity, they provide an area of refuge, and they allow time for occupants to egress a structure. To be effective, these fire barriers must be installed in accordance with their listing, and be free of any openings that could allow for the transport of smoke, heat, and fire from one side to the the other.

Throughout the construction process and the building's lifespan it becomes necessary to penetrate these barriers due to installation of building systems and components. In today's ‘connected’ buildings a main source of these penetrations comes from the need for network cabling to support data and communications networks.

Shows Overfilled Sleeves with firestop only installed on the top side of the sleeve.

Model codes have recognized that this will occur, and have included the following code language in their texts:

NFPA 101: - “Penetrations for accommodate...communications systems shall be protected by a fire stop system or device…”

IFC 703.1 - “Openings made therein [in fire-resistance-rated construction] for the passage of pipes...wires...and holes made for any reason shall be protected with approved methods capable of resisting the passage of smoke and fire.”

As cable networks expand, often times firestop materials are removed and not replaced.  As new cable displaces the firestop system, eventually the system is rendered non-code compliant. Fire inspection personnel should be aware of these conditions and ensure that cable sleeves are properly sealed and the fire-resistance-rating of the floor or wall assembly remains intact.
Here is a checklist of items that can be used to measure the reliability of a properly sealed cable sleeve:
  • The third-party tested and listed firestop systems will specify the permissible cable load.
  • The cable load for standard cable sleeves is calculated.  The calculated cable load is the aggregate cross-sectional area of cables as a percentage of the aggregate cross-sectional area of the sleeve.  What may appear to be a 50% visual fill, might actually be half that when calculated due to interstitial space between grouped cables.
  • Sleeves with missing or partially removed firestopping need to be repaired and cable fill percentage for the listed firestop system should be verified to ensure system remains compliant.
  • Firestop systems are mostly installed symmetrically on both sides of the wall or on top side of the floor.  However, listed firestop systems will provide greater detail.
  • Firestop materials are often red, but do not necessarily have to be.  There are no code related requirements that dictate color.
  • Listed and labeled purpose-made devices with integrated firestopping systems are available to replace traditional cable sleeves or to retrofit existing sleeves.
With the myriad of items that a fire inspector is responsible for looking at, this can prove to be one of the most critical. Having a clear understanding of fire-resistance-rated construction, fire stopping materials, and listed systems and components, can provide a more clear perspective on what to look for during inspection.  
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