Article Summary
- Atlanta commercial kitchens deal with a predictable set of exhaust system problems that show up repeatedly across different restaurant types, building ages, and cooking styles throughout the city.
- Most exhaust system problems don’t develop overnight. They build gradually through a combination of deferred maintenance, incomplete cleaning, equipment wear, and design issues that were never addressed after the original installation.
- Several of the most common problems are invisible from the kitchen floor during normal service, which is why they tend to go undetected until a professional cleaning or a fire inspection brings them to light.
- Each problem identified in this article has a specific cause, a specific set of symptoms, and a specific corrective action. Understanding all three makes it possible to address problems at the right level rather than treating symptoms without fixing the underlying issue.
- The Atlanta Fire Rescue Department and Fulton County Fire and Emergency Services cite many of these problems as recurring violations across commercial kitchen inspections in the metro area.
- Professional hood cleaning that covers the complete exhaust system from hood to rooftop is the most direct and most effective intervention for the majority of problems on this list.
- Because hidden exhaust flaws and ongoing wear gradually impair exhaust performance across metro facilities, discovering how Atlanta restaurant owners can improve kitchen airflow and ventilation helps operators systematically resolve root issues before facing regulatory citations.
Why the Same Problems Keep Appearing
Walk through enough commercial kitchens across Atlanta and a pattern emerges quickly. From the dense restaurant corridors of Buckhead and Midtown to the converted industrial kitchens in West Midtown and the neighborhood spots scattered through Decatur, East Atlanta, and College Park, the exhaust system problems inspectors and cleaning technicians find are remarkably consistent.
That consistency isn’t a coincidence. Exhaust system problems in commercial kitchens cluster around a predictable set of causes: deferred maintenance, incomplete cleaning, equipment age, original design limitations, and operational changes that weren’t reflected in corresponding maintenance adjustments. These causes exist in every active commercial kitchen market, and Atlanta’s combination of high cooking volumes, older building stock, and a demanding regulatory framework makes them particularly visible here.
Understanding which problems are most common, what causes them, and what they look like in practice is genuinely useful for Atlanta restaurant operators. It makes it possible to identify emerging problems before they become serious violations, to communicate more effectively with professional cleaning companies and HVAC contractors, and to make better decisions about maintenance schedules and capital expenditures.
This article works through the most common exhaust system problems found in Atlanta commercial kitchens in detail. Each one includes a description of what’s happening physically, the symptoms that signal its presence, and the corrective action that actually addresses it rather than just masking the symptom.
Problem #1: Grease Accumulation Beyond Safe Thresholds
This is the most common exhaust system problem found in Atlanta commercial kitchens, and it’s the one that drives the largest share of fire inspection violations across both city and county jurisdictions.
What’s happening: Grease accumulation beyond safe thresholds means the grease deposits inside the hood, duct system, exhaust fan, and rooftop have reached levels that NFPA 96 considers a meaningful fire risk. The accumulation has exceeded what the cleaning schedule is removing, either because the schedule is set at the wrong frequency for the kitchen’s actual cooking volume, because the cleaning being performed isn’t reaching all parts of the system, or because the cleaning has simply been deferred past its required interval.
The grease doesn’t accumulate evenly. It builds fastest at:
- Directional changes in the duct run, where inertia carries particles to the outer wall of turns
- Horizontal duct sections, where gravity settles particles to the bottom surface
- The plenum chamber behind the baffle filters
- Exhaust fan impeller blades and housing
- The rooftop surface around the fan discharge point
Symptoms:
- Visible grease coating on the plenum interior, ranging from a light film to a thick, darkened layer depending on how overdue the cleaning is
- Grease dripping from the filter rack or pooling in the drip trough
- Dark, tacky residue on the hood’s exterior face
- Service sticker showing a cleaning date that exceeds the NFPA 96-required interval for the kitchen’s cooking type
- Visible grease accumulation on the exhaust fan housing or rooftop during a rooftop inspection
Corrective action: Professional hood cleaning that covers the complete exhaust system — hood canopy, plenum, baffle filters, grease collection components, duct interior through all accessible panels, exhaust fan assembly, and rooftop discharge area — performed to NFPA 96’s bare-metal standard. After the cleaning, the forward-going schedule needs to be set at the correct NFPA 96-required frequency for the kitchen’s actual cooking type and volume, not a generic assumption.
The frequency requirements under NFPA 96 that Atlanta kitchens need to follow:
- Monthly: Solid-fuel cooking (wood, charcoal), high-volume charbroiling, wok cooking, 24-hour operations
- Quarterly: Moderate-volume cooking with fryers, griddles, and standard commercial ranges
- Every 6 months: Low-volume cooking, limited hours, pizza or oven-based menus
- Annually: Very low-volume operations, seasonal use, churches, camps
Problem #2: Incomplete Cleaning That Misses Critical System Sections
This problem is more prevalent in Atlanta commercial kitchens than operators realize, largely because the signs of it aren’t immediately apparent after a cleaning visit. The hood looks cleaner, a service sticker has been applied, and the operator believes the system has been properly serviced. The problem is that the cleaning stopped at the visible surfaces and never reached the duct interior, the exhaust fan, or the rooftop.
What’s happening: Some hood cleaning companies, particularly those competing primarily on price, limit the scope of their service to the visible surfaces of the hood canopy and the exterior of the baffle filters. This approach produces a hood that looks cleaner after the visit but leaves the grease accumulation in the duct system, on the fan impeller, and on the rooftop completely unaddressed. The service sticker and the invoice say a cleaning happened. NFPA 96’s bare-metal standard was not met for the complete system.
Over time, a kitchen receiving this type of incomplete service accumulates grease in the duct interior and exhaust fan at the same rate as a kitchen receiving no service at all, because the incomplete cleaning doesn’t touch those components. The first time a professional cleaning company opens the access panels in a kitchen that’s been receiving incomplete service for a year or more, they often find significant and sometimes alarming grease accumulation that the periodic sticker dates on the hood suggested shouldn’t be there.
Symptoms:
- Cleaning visits that are completed in an unusually short time, typically under an hour for a standard single-hood system
- Service reports that don’t specifically describe duct cleaning, exhaust fan cleaning, or rooftop work
- No before-and-after photographs provided after service, or photographs that only show the hood face
- Persistent smoke in the kitchen and degraded capture velocity despite recent cleaning visits
- Visible grease accumulation on the exhaust fan or rooftop that’s inconsistent with the cleaning history
Corrective action: Switch to a professional hood cleaning company that explicitly includes the complete exhaust system in every service. Before engaging a new company, ask directly:
- Does your service include the duct interior?
- Do your technicians go to the roof to clean the exhaust fan?
- Do you provide before-and-after photographs of the duct interior accessed through access panels, the exhaust fan, and the rooftop?
- How long does a complete service typically take for a kitchen of this size?
A company that can answer all of these questions specifically and confidently is performing a different level of service than one that hedges or answers vaguely. After switching to a complete-system cleaning provider, the first service on a kitchen that’s been receiving incomplete cleaning may uncover significant accumulation in the duct system that requires additional time and effort to bring to bare metal.
Problem #3: Missing, Damaged, or Incorrectly Installed Baffle Filters
Baffle filters are the workhorses of the grease separation process in a commercial exhaust system, and problems with them affect both fire safety and system performance immediately and continuously.
What’s happening: Filter problems in Atlanta commercial kitchens fall into several categories. Missing filters, where a position in the filter rack is simply empty, allow unfiltered grease vapor to enter the duct system directly through the gap. Damaged filters, where the baffle geometry has been bent, cracked, or distorted by impact or improper handling, no longer separate grease particles effectively. Incorrectly installed filters, positioned upside down or backward relative to their designed airflow direction, also fail to provide effective grease separation. And filters that are so heavily loaded with hardened grease that they’re effectively solid panels restrict airflow severely while providing minimal additional grease capture benefit.
Each of these conditions has a direct consequence for the duct system: more grease vapor passes through to the duct interior than the system was designed to handle, accelerating accumulation in the ductwork and at the exhaust fan.
Symptoms:
- Visible gap in the filter array where a filter is missing
- Filters that are visibly bent, cracked, or deformed
- Grease accumulation patterns in the plenum that are heavier at specific locations corresponding to filter gaps or damaged filter positions
- Baffle channels that are completely closed by hardened grease accumulation
- Significantly reduced airflow through the hood despite a functioning exhaust fan
Corrective action: Inspect the filter array during each cleaning service and address any problems found:
- Replace missing filters with correctly sized and rated replacement units
- Replace damaged filters that can’t be restored to their designed geometry through cleaning
- Reinstall any filters that are positioned incorrectly, confirming the correct orientation per the filter manufacturer’s instructions
- For severely loaded filters, replacement rather than cleaning may be the more practical option if the accumulated grease has hardened to the point where cleaning can’t restore the designed open area
Filter inspection and correction should be part of every professional hood cleaning service. Between professional cleanings, kitchen staff performing regular filter cleaning should note and report any filter damage or missing positions so they can be addressed before the next professional service.
Problem #4: Inaccessible Duct Sections Without Proper Access Panels
This is a structural problem that’s particularly common in Atlanta’s older commercial buildings and in kitchens that have been modified over the years without attention to duct access requirements.
What’s happening: NFPA 96 requires that grease ducts be accessible for cleaning and inspection at specific intervals along the duct run. Access panels must be present at the top and bottom of vertical risers, at changes of direction, at the beginning and end of horizontal runs, and at other specified locations. In kitchens where the duct system was installed before current access requirements were standard, or where building renovations have enclosed previously accessible duct sections, some portions of the duct run may not be reachable for cleaning.
In Atlanta’s commercial building stock, this problem shows up frequently in:
- Historic storefronts along corridors like Marietta Street, Auburn Avenue, and Ponce de Leon that have been converted to restaurant use
- Warehouse and industrial conversions in West Midtown, Westside, and the areas around the Beltline
- Multi-tenant buildings where the duct system passes through spaces shared with other tenants
- Kitchens where ceiling or wall modifications during previous renovations enclosed previously accessible duct sections
When a duct section can’t be accessed, it can’t be cleaned. Grease accumulates in those sections at the same rate as the rest of the system, but the cleaning never reaches it. Over time, the inaccessible sections become the highest-risk portions of the duct system because they’ve been accumulating grease without interruption since the last time the duct was fully accessible, which may be years or decades.
Symptoms:
- Access panel locations that don’t align with NFPA 96’s required spacing
- Duct sections that pass through finished ceilings or walls without accessible panels
- A professional cleaning report that notes specific duct sections couldn’t be cleaned due to access limitations
- An inspector’s notation that duct access doesn’t meet current code requirements
Corrective action: This problem requires a structural correction rather than a maintenance adjustment. A qualified contractor needs to assess the duct system against current NFPA 96 access requirements and install properly constructed and labeled access panels at the required locations. In some cases, this means cutting through finished ceilings or walls to install panels in enclosed sections. The work typically requires a mechanical permit and may require fire code review by the Atlanta Fire Rescue Department or the relevant county authority.
The cost of adding access panels is real and sometimes significant in complex older buildings. But the alternative, a duct system with sections that can never be cleaned, is a fire code violation and a persistent, unaddressable fire risk. It’s also a problem that doesn’t resolve itself over time. Every service period that passes without accessible panels is another period of grease accumulation in sections that can’t be cleaned.
Problem #5: Exhaust Fan Running at Reduced Capacity
The exhaust fan is the mechanical heart of the exhaust system, and problems with it affect the performance of every other component in the system.
What’s happening: Exhaust fan capacity reduction in Atlanta commercial kitchens has several common causes. Grease accumulation on the impeller blades is the most frequent, as described in detail in previous articles in this series. Beyond grease accumulation, belt-driven fans can lose capacity when the drive belt wears, stretches, or slips. Fan motor issues, including bearing wear from grease-imbalance vibration, motor winding deterioration in units that have been running in hot, grease-laden environments for years, and contactor or starter issues in the electrical control circuit, also reduce effective fan output. Finally, physical damage to impeller blades from debris drawn into the fan housing occasionally occurs in Atlanta kitchens where the intake is not properly protected.
A fan running at significantly reduced capacity affects the entire exhaust system simultaneously. Capture velocity at the cooking surface decreases. Grease vapors escape the capture zone and migrate through the kitchen. The kitchen runs hotter. Energy consumption for the motor may increase even as airflow output decreases, as the motor works harder against the same resistance with reduced mechanical efficiency.
Symptoms:
- Visible smoke lingering in the kitchen during service
- Kitchen running noticeably hotter than it used to at the same cooking load
- Grease accumulation on kitchen walls and ceilings accelerating between cleaning visits
- Audible change in fan noise, either reduced output noise or increased vibration noise
- Cooking odors escaping into the dining room
- Energy bills increasing without a corresponding change in cooking volume or equipment
Corrective action: The corrective action depends on the cause:
- Grease accumulation on the impeller: Professional cleaning that includes the exhaust fan assembly, performed at the correct NFPA 96-required frequency going forward
- Belt wear or slippage: Inspection and replacement of the drive belt by a qualified service technician
- Bearing wear: Bearing inspection and replacement; in cases of advanced wear, the motor assembly may need replacement
- Motor issues: Electrical and mechanical assessment by a qualified technician; motor replacement if the motor is failing
- Blade damage: Assessment of the impeller assembly; blade repair or impeller replacement as warranted
For exhaust fans that have been in service for many years in high-volume Atlanta kitchens, a comprehensive mechanical assessment alongside the next professional cleaning is a worthwhile investment. Fans that are approaching the end of their service life are better replaced proactively than reactively when they fail during a busy service period.
Problem #6: Grease Duct Joint Leakage
Duct joint integrity is a structural issue that carries significant fire safety implications and is more common in older Atlanta kitchen installations than most operators realize.
What’s happening: NFPA 96 requires that grease duct joints be continuously welded to prevent grease leakage. In duct systems that were installed before current welding requirements were standard, or in systems where the original welding quality was poor, joints can develop gaps or separations over time. When grease accumulates at these gaps and begins to migrate through, it deposits on the building materials surrounding the duct, creating a fire risk outside the duct itself.
In Atlanta’s older commercial buildings, duct systems that were installed decades ago may have been built to standards that didn’t require continuous welding or that permitted construction methods no longer considered acceptable. These older installations often have joint conditions that would not pass a current code review.
Duct joint leakage is also sometimes caused by structural movement in the building. In Atlanta’s clay-heavy soils, seasonal ground movement can affect buildings enough to put stress on fixed duct installations, potentially opening joints that were originally sound.
Symptoms:
- Grease staining on the exterior surface of the duct at joint locations
- Grease deposits found on ceiling surfaces, wall surfaces, or structural elements near the duct run
- Visible gaps or separations at duct joints when inspected through access panels
- Smoke or grease odors in ceiling spaces adjacent to the duct run
- An inspector’s notation of duct leakage in an inspection report
Corrective action: Duct joint leakage requires assessment by a qualified contractor to determine the extent of the problem and the appropriate repair method. For joints with minor separation, professional sealing using approved materials may be sufficient. For joints with significant separation or for duct systems where multiple joints show leakage, more extensive repair or duct section replacement may be warranted.
In some Atlanta kitchens, particularly those in historic buildings or older commercial spaces, duct joint assessment reveals construction that doesn’t meet current NFPA 96 standards in ways that go beyond joint sealing and require more comprehensive duct system evaluation and potential replacement. This is a significant finding but not an uncommon one in the city’s older restaurant spaces.
Problem #7: Inadequate Hood-to-Equipment Coverage
This is a configuration problem that develops gradually in most kitchens as equipment is added, relocated, or changed over time, and it creates fire safety and compliance problems that cleaning alone can’t address.
What’s happening: NFPA 96 specifies minimum overhang dimensions for hoods over cooking equipment, the distance the hood canopy must extend beyond the cooking surface on all sides to capture vapors rising from the entire cooking area. When cooking equipment is repositioned so that it extends beyond the hood’s overhang dimensions, or when equipment is added outside the existing hood’s coverage area, the uncovered portions of the cooking surface generate vapors that aren’t captured by the exhaust system.
In Atlanta’s active restaurant market, where menus and cooking equipment evolve regularly, this problem develops incrementally. A catering function adds a portable induction range at the end of the cooking line, just outside the hood’s coverage zone. A new charbroiler replaces an older griddle but is positioned slightly differently because of supply connections. A kitchen reorganization shifts the cooking line a few feet without anyone assessing the impact on hood coverage. Over time, the relationship between the cooking equipment and the hood has changed enough that the coverage is meaningfully compromised.
Symptoms:
- Visible smoke rising from cooking equipment and immediately spreading into the kitchen rather than being captured by the hood
- Grease accumulation on kitchen surfaces in areas near cooking equipment that’s operating outside the hood’s capture zone
- An inspector’s notation that cooking equipment extends beyond the hood’s effective coverage area
- Accelerated grease accumulation throughout the kitchen, suggesting that significant vapor is escaping the capture zone
Corrective action: The first step is assessing the actual coverage relationship between the existing hood and the current equipment layout. This involves measuring the hood’s overhang dimensions and comparing them to the actual positions of all cooking equipment currently in operation.
If the issue is that equipment has simply drifted outside the hood’s intended coverage zone, repositioning the equipment back within the coverage area is the simplest fix. If cooking equipment additions have genuinely expanded the cooking area beyond what the existing hood covers, the hood needs to be extended or supplemented to provide coverage for the new equipment positions. Hood extension or addition is a more significant project requiring permitting, fire suppression system evaluation, and review against current NFPA 96 and IMC requirements.
Problem #8: Grease Collection System Failures
The grease collection components of the exhaust system, including the drip troughs, grease cups, and any rooftop containment systems, are a common source of problems in Atlanta commercial kitchens. They tend to be lower-profile than the hood and duct components but create both fire safety and compliance issues when they’re not functioning properly.
What’s happening: Grease collection failures take several forms. Drip troughs and grease cups that aren’t emptied regularly overflow, allowing collected grease to spill onto the filters below, onto the cooking equipment, or onto the kitchen floor. Collection cups that are damaged, missing, or improperly positioned don’t collect drips effectively, allowing grease to migrate to surfaces where it creates hazards. At the rooftop level, exhaust fans without proper grease containment at the discharge point allow grease to accumulate freely on the rooftop membrane.
In high-volume Atlanta kitchens running through extended service hours, grease collection components can reach capacity within a single service period. A grease cup that was emptied before the dinner service may be overflowing by the end of it if the cooking volume is high enough and the collection components are small.
Symptoms:
- Grease dripping from the filter rack onto cooking equipment below during service
- Grease pooling on the kitchen floor below the hood during or after service
- Missing or improperly positioned grease cups in the filter rack
- Grease staining on the cooking equipment surfaces directly below the filter rack
- Significant grease accumulation on the rooftop surface around the exhaust fan with no containment system in place
Corrective action:
- Overflowing collection components: Establish a regular emptying schedule for drip troughs and grease cups, with frequency based on cooking volume. High-volume kitchens may need daily emptying. The professional cleaning service should include cleaning the collection components to bare metal.
- Missing or damaged components: Replace missing or damaged drip troughs and grease cups with correctly sized replacement components compatible with the hood system.
- Rooftop containment: Install a listed grease containment system at the exhaust fan discharge point if one isn’t currently in place. Current NFPA 96 editions address rooftop grease containment, and Atlanta fire inspectors are increasingly attentive to this component during inspections.
Problem #9: Rooftop Grease Accumulation and Membrane Damage
Rooftop grease problems are among the most costly and structurally serious exhaust system problems found in Atlanta commercial kitchens, and they’re also among the least frequently addressed until the damage becomes significant.
What’s happening: Grease that escapes the exhaust fan discharge point accumulates on the rooftop surface surrounding the fan. Without a properly functioning containment system, this grease spreads across the rooftop membrane under the influence of gravity, wind, and rain. Atlanta’s rainfall distributes rooftop grease across a wider area than kitchens in drier markets experience.
The consequences develop in layers. The immediate layer is fire risk from combustible material on the rooftop surface. The intermediate layer is roofing membrane damage as grease penetrates and degrades the membrane material. The long-term layer is structural damage as water infiltrating through a grease-compromised membrane affects the building’s interior spaces.
In Atlanta’s many mixed-use commercial buildings, where restaurants occupy ground-floor space beneath residential or office tenants, rooftop grease damage from the restaurant’s exhaust system can affect other building occupants in ways that create serious liability exposure for the restaurant operator.
Symptoms:
- Visible grease staining spreading across the rooftop membrane in a pattern radiating from the exhaust fan location
- Soft or compromised roofing material in the area surrounding the exhaust fan that feels different underfoot from sound roofing
- Grease accumulation on adjacent HVAC equipment, skylights, or rooftop structures
- Evidence of water intrusion in the ceiling of the kitchen or adjacent interior spaces below the affected rooftop area
- Visible grease on the fan housing, base, and curb mount
Corrective action:
The corrective action for rooftop grease problems operates at two levels. The immediate level is professional cleaning of the rooftop area as part of a complete hood cleaning service, removing accumulated grease from the fan assembly and the surrounding rooftop surface. This should happen with every professional cleaning service.
The structural level involves having the rooftop membrane assessed for damage by a qualified roofing contractor. Areas of grease-compromised membrane may need to be repaired or replaced. In severe cases where grease accumulation has been extensive and long-standing, the repair scope can be substantial.
Going forward, installation of a listed rooftop grease containment system at the exhaust fan discharge point prevents new accumulation from developing beyond the containment device, protecting the roofing membrane and reducing the scope of cleaning required at each service visit.
Problem #10: Documentation and Service Record Gaps
This is a compliance problem rather than a physical system problem, but its consequences are as real as any physical deficiency during an Atlanta fire inspection.
What’s happening: Documentation gaps occur when:
- Professional cleaning happens but the service company doesn’t provide a written report or photographs
- Service stickers are applied but are missing required information like the cleaning date or company name
- Service records from previous cleanings weren’t retained and can’t be produced for an inspector
- The cleaning history shows intervals that exceed the NFPA 96-required frequency for the kitchen’s cooking type
- A change of ownership or management resulted in service records not transferring to the current operator
Any of these conditions means that even a kitchen that’s being cleaned properly can’t demonstrate compliance during an inspection. And a kitchen that can’t demonstrate compliance is treated as non-compliant regardless of its physical condition.
Symptoms:
- No service sticker visible on the hood, or a sticker that’s too old relative to the required cleaning frequency
- No written service report on file from the most recent cleaning
- Unable to produce service records going back at least 12 months when an inspector asks
- Service records that exist but show cleaning intervals longer than NFPA 96 requires for the kitchen’s cooking type
Corrective action:
The documentation corrective action is straightforward but requires immediate attention:
- Contact the current cleaning company and request copies of all service reports they have on file for the kitchen
- If service records are incomplete or unavailable from the current provider, consider this when evaluating whether to continue with that provider
- Schedule a professional cleaning with a company that provides complete documentation as standard practice, including a detailed service report and time-stamped before-and-after photographs
- Create a dedicated compliance folder, physical or digital, where every service report is filed immediately upon receipt
- Establish a monthly check of the service sticker date against the required cleaning frequency so overdue cleanings are identified and scheduled before an inspection catches them
Going forward, treat documentation as a non-negotiable deliverable of every cleaning service. A company that can’t produce a detailed service report with photographs after every visit isn’t providing what NFPA 96 compliance actually requires.
Problem #11: Fire Suppression System Coverage Gaps
While fire suppression systems are a separate system from the exhaust ductwork, they interact with the exhaust system closely enough that coverage gaps are appropriately addressed in this context. They’re also a common finding in Atlanta commercial kitchen inspections.
What’s happening: Fire suppression coverage gaps develop when cooking equipment moves, changes, or is added after the suppression system was designed and installed. The suppression nozzles are positioned to deliver agent to specific cooking surfaces based on the equipment layout at the time of installation. When equipment shifts, even by a foot or two, the nozzle that was designed to protect a specific burner may no longer be aimed at that burner’s actual position.
Coverage gaps also develop when cooking equipment is replaced with a different type. A griddle that’s replaced with a charbroiler presents a different fire risk profile and may require different nozzle positions or agent types than the original equipment.
In Atlanta’s active restaurant market, where menus and equipment evolve frequently, this problem is common. Many kitchen operators don’t realize that equipment changes have suppression coverage implications until an inspector or suppression system service technician identifies the gap.
Symptoms:
- Suppression system service report noting nozzle coverage that doesn’t match the current equipment layout
- Cooking equipment that has been moved or added since the last suppression system inspection
- An inspector’s notation that suppression coverage doesn’t adequately protect all cooking equipment
- Visible cooking equipment that doesn’t have a nozzle positioned above it within the coverage design
Corrective action: Have the fire suppression system inspected and coverage assessed by a licensed fire suppression service provider any time cooking equipment is moved, added, or replaced. Don’t wait for the scheduled semi-annual inspection if equipment changes have occurred in the interim. Nozzle repositioning or addition should be performed to restore complete coverage, and the suppression system’s connection to the gas shut-off should be verified as part of the assessment.
Problem #12: Degraded Hood Seals and Gaps in the Hood Assembly
This is a structural problem that’s often overlooked during standard cleaning visits but creates both fire safety and performance issues in the kitchens where it occurs.
What’s happening: Commercial kitchen hoods are assembled from multiple components, including the canopy sections, the plenum, the filter rack, and the connection collar to the duct system. The joints and seams between these components are designed to be grease-tight, preventing grease from migrating outside the designed pathway. When the sealant or fasteners at these joints degrade, gaps develop. Grease can migrate through the gaps onto adjacent surfaces. Air can infiltrate or escape at unexpected locations, disrupting the designed airflow pattern in the hood.
In Atlanta’s older kitchen installations, hood assemblies that have been in place for many years may have deteriorating seals or fasteners that have loosened through the vibration of continuous operation.
Symptoms:
- Grease deposits found on the exterior surfaces of the hood assembly at locations other than the filter face or discharge collar
- Visible gaps or separations in the hood assembly at seam locations
- Airflow patterns around the hood that seem inconsistent with the designed capture zone
- Grease staining on kitchen ceiling surfaces adjacent to the hood assembly that doesn’t correspond to filter gaps
Corrective action: Hood assembly gaps and seal failures should be assessed by a professional cleaning company or a qualified kitchen equipment contractor. Minor seal failures can sometimes be addressed with appropriate sealant products approved for grease duct applications. More significant structural failures in the hood assembly may require fabrication repair or component replacement.
How These Problems Interact
One characteristic of exhaust system problems in Atlanta commercial kitchens that’s worth naming explicitly is that they rarely occur in isolation. Several of the problems in this article create conditions that accelerate or worsen other problems on the list.
Grease accumulation beyond safe thresholds worsens when baffle filters are damaged or missing, because the filtration that’s supposed to reduce grease loading in the duct system is compromised. Exhaust fan capacity reduction worsens when duct joint leakage is present, because the fan is working against a system that isn’t delivering the designed airflow resistance. Rooftop grease accumulation accelerates when the exhaust fan is running at reduced capacity due to imbalance, because the fan is less effective at containing grease at the discharge point.
When a professional cleaning company or an inspector finds one of these problems in an Atlanta commercial kitchen, it’s worth assessing whether other problems on this list are also present. The presence of one often signals that the overall system has been under-maintained, and a comprehensive assessment rather than a targeted correction of the single identified problem is the more reliable path to genuine compliance.
Preventing These Problems Before They Require Correction
The most practical takeaway from this list is that the majority of these problems are either directly caused by inadequate maintenance or significantly worsened by it. Only a handful, specifically the access panel issues, duct joint failures, hood assembly structural problems, and the coverage design issues, are primarily caused by factors other than maintenance.
For the maintenance-driven problems, the prevention strategy is straightforward:
- Schedule professional hood cleaning at the correct NFPA 96-required frequency for the kitchen’s cooking type and volume
- Ensure the cleaning company covers the complete system, from baffle filters through the duct interior to the exhaust fan and rooftop
- Perform regular in-house filter cleaning between professional service visits
- Empty grease collection components on a schedule appropriate to cooking volume
- Maintain service documentation and check the sticker date monthly
- Have the fire suppression system inspected semi-annually and any time equipment changes occur
- Schedule a mechanical inspection of the exhaust fan periodically, not just cleaning
For the structural problems, the prevention strategy involves periodic professional assessment of the duct system, particularly in older Atlanta buildings and in kitchens that have undergone modifications, to identify access, joint integrity, and coverage issues before they become serious violations.
Getting Ahead of These Problems Before They Find You
The problems in this article are common in Atlanta commercial kitchens not because operators are careless but because exhaust systems accumulate problems in parts of the building that most people never see, on timelines that don’t align with any obvious operational event, in ways that don’t produce a dramatic warning sign until the accumulation has been happening for a long time.
The Atlanta Fire Rescue Department and Fulton County Fire and Emergency Services find these problems during inspections because that’s often the first time anyone looks at the system systematically. The operators who aren’t surprised by what those inspections find are the ones whose professional cleaning company is looking at the same things the inspector looks at, every service visit, and communicating what they find.
Premier Grease has been finding and addressing these problems in Atlanta commercial kitchens since 2001. Every service we perform covers the complete exhaust system, from baffle filters through the duct interior to the exhaust fan assembly and the rooftop discharge area, cleaned to NFPA 96’s bare-metal standard. After each service, you receive a detailed report with time-stamped before-and-after photographs documenting the system’s condition before cleaning and confirming the work performed. If we find something that needs attention beyond what cleaning can address, we communicate it clearly so you can take action before it becomes a violation.
No contracts. Licensed, bonded, and insured with $5 million in general liability coverage. We work around your operating hours across the Atlanta metro area, including all of Fulton County, DeKalb County, Gwinnett County, Cobb County, and surrounding areas within our 100-mile service radius.