The Innocent Question That Isn’t
How a legitimate engineering question gets weaponised to justify undersized equipment and shift blame to operators
“What temperature will your product be when you load it?”
Every frozen food courier hears this question from TRU builders, fleet suppliers, and refrigeration agents. It sounds reasonable. Professional, even. Like someone doing their due diligence before specifying equipment.
It’s actually a trap.
Not because the physics is wrong—product temperature genuinely matters to thermal load calculations. The trap is in how this question gets used: to justify smaller, cheaper equipment upfront, then deflect blame when that equipment inevitably fails under real-world conditions.
Welcome to the cold chain industry’s favourite liability shield.
The Physics Is Real
Let’s be clear: product temperature absolutely affects refrigeration load. This isn’t disputed.
Loading 500kg of product at -10°C instead of -18°C creates measurable pull-down demand:
Pull-down energy required:
Q = mass × specific heat × temperature difference
Q = 500 kg × 2.0 kJ/kg·K × 8K
Q = 8,000 kJ = 8 MJ
If you need to restore -18°C within 2 hours:
Power required = 8 MJ / 7,200 seconds = 1.1 kW additional load
That’s 1.1 kW of continuous cooling capacity consumed just pulling product from -10°C to -18°C. On top of steady-state losses, door opening infiltration, solar gain, and urban heat island effects.
For a system already running at capacity, this additional load causes temperature drift. The physics is undeniable.
So why call it a trap?
Where Physics Becomes Weaponry
The problem isn’t the question. It’s when and why it gets asked.
Scenario 1: Before the sale
TRU agent asks about product temperature during specification. You say “-18°C” because that’s what frozen product should be. Agent sizes equipment for “maintain -18°C” duty—the minimum possible specification.
Scenario 2: After the failure
Six months later, your cargo space can’t hold temperature during summer routes. You call the agent. First question: “What temperature was the product when you loaded it?”
See the pattern?
The question creates an unfalsifiable escape hatch. Nobody measures core product temperature at every collection point. Nobody has a temperature log from the supplier’s cold store. The agent knows this.
“Your product must have been too warm” becomes the default explanation for any temperature excursion. Equipment undersizing? Altitude effects? Inadequate door opening recovery? All invisible behind the product temperature excuse.
The Courier Paradox
Here’s where this question reveals its fundamental dishonesty when applied to courier operations.
A courier collects product from multiple suppliers and delivers to multiple customers. We don’t pack the product. We don’t run the cold stores. We don’t control the loading dock practices at the 15 different collection points on a typical route.
We transport whatever shows up.
When a supplier hands us product at -14°C instead of -18°C, what exactly are our options?
- Refuse the cargo? (Lose the customer, breach the contract)
- Accept it and hope? (Gamble with someone else’s product)
- Pull it down during transport? (Need equipment sized for pull-down, not just maintain)
Option three is the only professional answer. But that requires equipment specification conversations that start with “what’s your worst-case incoming product temperature?” not “what should your product temperature be?”
A courier’s refrigeration system must handle reality, not ideals.
What the Question Actually Reveals
When a TRU builder or agent asks about product temperature, they’re telling you something important about their sizing methodology. Listen carefully.
Red flag responses to watch for:
| What they ask | What it reveals |
|---|---|
| “Product will be -18°C, right?” | Leading question seeking confirmation for minimum spec |
| “We size for maintain, not pull-down” | Acknowledging they won’t handle real-world variance |
| “Pull-down is extra capacity you’ll pay for” | Framing proper sizing as unnecessary expense |
| “That’s cold store equipment, not transport” | Deflecting responsibility for thermal recovery |
What proper engineering sounds like:
| What they ask | What it reveals |
|---|---|
| “What’s your worst-case incoming temp?” | Planning for reality, not ideals |
| “How many stops, what door opening frequency?” | Understanding your actual duty cycle |
| “What altitude are you operating at?” | Accounting for capacity derating |
| “Do you need pull-down capability or just maintain?” | Honest conversation about specifications |
The difference between these approaches is the difference between selling you equipment and solving your problem.
The Liability Transfer Game
Let’s map the full liability transfer:
At specification:
- Agent asks about product temperature
- You confirm -18°C (because that’s compliant frozen food)
- Agent documents this assumption
- Equipment sized for ideal conditions
- Lower quote wins the job
During operation:
- Product arrives at -14°C (common in South African supply chains)
- System lacks pull-down capacity
- Temperature drifts above -15°C during route
- Cargo compromised
At the complaint:
- “What temperature was product at loading?”
- “Your product must have been out of spec”
- “Our equipment is rated for -18°C maintain”
- “This isn’t a warranty issue”
The documented assumption from specification becomes the liability shield at failure. Your signature on that spec sheet transfers all risk to you.
Quantifying the Sizing Gap
Let’s calculate what “maintain” vs “realistic” sizing actually means for a typical Gauteng courier operation.
Scenario: 12m³ cargo space, summer route, 15 stops
“Maintain -18°C” sizing (what agents typically quote):
Steady-state losses: 1.5 kW
Safety margin (20%): 0.3 kW
Sea-level rating: 1.8 kW
Reality-based sizing:
Steady-state losses: 1.5 kW
Door opening recovery (30 openings): 0.4 kW average
Urban heat island addition: 0.4 kW
Product pull-down allowance (4K variance): 0.5 kW
Peak recovery requirement: 1.2 kW additional
Subtotal: 4.0 kW at altitude
Altitude correction (Johannesburg, 21% derating):
Sea-level rating required: 4.0 / 0.79 = 5.1 kW
Safety margin (25%): 6.4 kW specification
The gap: 1.8 kW vs 6.4 kW specification
That’s not a rounding error. That’s equipment undersized by a factor of 3.5.
The “maintain -18°C product” assumption contributes about 0.5 kW to this gap—roughly 8% of actual requirement. Important, but dwarfed by door opening loads (10%), altitude effects (21%), and peak recovery needs (30%).
Product temperature is real. It’s also convenient cover for everything else wrong with the specification.
The Questions That Should Be Asked
If a TRU agent is genuinely engineering a solution rather than selling a product, here’s what the conversation should include:
About your operation:
- How many stops per route?
- Average door opening duration?
- Operating altitude(s)?
- Summer ambient temperature exposure?
- Urban vs highway ratio?
About thermal loads:
- Do you need pull-down capability?
- What’s your realistic worst-case incoming product variance?
- How quickly must you recover after door openings?
- What’s your temperature excursion tolerance?
About specification philosophy:
- How do you derate for altitude?
- What safety margin do you build in?
- How do you account for equipment aging?
- What’s the warranty position on thermal excursions?
If the conversation focuses primarily on product temperature while skipping these questions, you’re being set up for blame transfer, not specification.
Protecting Your Operation
Document everything:
- Request written confirmation of altitude derating applied
- Get door opening frequency assumptions in writing
- Ask for pull-down capacity specification, not just maintain
- Confirm what temperature variance is covered by warranty
Specify for reality:
- Assume product will arrive 4-6K above ideal (because it will)
- Size for your actual door opening frequency
- Apply Johannesburg altitude correction (minimum 25% oversizing)
- Build in peak recovery capacity for summer conditions
Shift the question: When asked “what temperature will product be?”, respond with:
“We’re a courier operation. Product temperature at collection varies based on supplier practices we don’t control. What pull-down capacity does your specification include for product arriving at -12°C to -14°C? And how does that interact with your altitude derating and door opening recovery assumptions?”
Watch how quickly the conversation changes.
The Honest Answer
Does product temperature matter? Yes.
Should it be the primary sizing question for courier operations? No.
A courier’s refrigeration system faces thermal loads from altitude, door openings, ambient conditions, urban heat, and product variance. Product temperature is one factor among many—and unlike the others, it’s the only one the operator cannot control.
When TRU agents lead with product temperature, they’re not being thorough. They’re selecting the one variable that shifts blame from equipment specification to operator practice.
The physics is real. The weaponisation is the problem.
For TRU Builders Reading This
We’re not saying product temperature is irrelevant. We’re saying it’s one variable in a multi-factor equation that gets disproportionate attention because it’s convenient for liability purposes.
If you want to be a solutions provider rather than an equipment vendor:
- Lead with duty cycle questions, not product temperature assumptions
- Specify pull-down capacity for courier applications—it’s not optional
- Apply altitude corrections prominently in Gauteng quotations
- Build safety margins that account for real-world variance
- Stop using product temperature as the first line of defence when systems underperform
The operators who understand thermodynamics will find suppliers who engineer solutions. The ones who don’t will keep buying undersized equipment and blaming warm product.
Choose which market you want to serve.
Conclusion
“What temperature will your product be?”
It’s a legitimate engineering question wrapped in a liability transfer mechanism. The physics is real. The way it’s used in South African transport refrigeration specification is not.
For courier operations:
- You cannot control incoming product temperature
- Your system must handle whatever shows up
- Specification should account for variance, not assume ideals
- Any agent leading with this question is sizing for minimum, not reality
The next time someone asks about your product temperature, ask them about altitude derating, door opening frequency, and pull-down capacity.
Their response will tell you whether they’re engineering a solution or setting up an excuse.
Related Reading
At The Frozen Food Courier, we specify equipment for reality: altitude-corrected capacity, multi-stop thermal loads, and yes—product temperature variance we cannot control. Because physics doesn’t accept excuses, and neither should you.
